Modeling with Equation/InequalityConstraints
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Algebra 2 › Modeling with Equation/InequalityConstraints
A rectangle is being designed for a poster. Let $L$ = length (in inches) and $W$ = width (in inches). The perimeter must be at most 40 inches, and the area must be at least 84 square inches. Also $L>0$ and $W>0$. Which system correctly represents these constraints?
$$\begin{cases}2L+2W\ge 40\\LW\ge 84\\L>0,\\ W>0\end{cases}$$
$$\begin{cases}2L+2W\le 40\\LW\le 84\\L>0,\\ W>0\end{cases}$$
$$\begin{cases}2L+2W\le 40\\LW\ge 84\\L>0,\\ W>0\end{cases}$$
$$\begin{cases}L+W\le 40\\LW\ge 84\\L>0,\\ W>0\end{cases}$$
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. A constraint is a limitation or requirement: 'budget at most $500' becomes cost ≤ 500, 'need at least 10 units' becomes quantity ≥ 10. The system of ALL constraints defines the feasible region—the set of all solutions that work. A solution is viable if it lies in this feasible region (satisfies every single inequality/equation) AND makes real-world sense (no negative quantities, whole units when needed, etc.). Even one violation makes it nonviable! The constraints are perimeter 2L + 2W ≤ 40 (at most 40 inches), area LW ≥ 84 (at least 84 sq in), and L > 0, W > 0 (positive dimensions). Choice A correctly represents all constraints with the full perimeter formula and ≥ for area. A distractor like Choice C uses L + W ≤ 40, which is only half the perimeter—remember perimeter is 2(L + W), so include the 2! Constraint identification from context: (1) list every limitation mentioned ('budget $X,' 'time ≤ Y hours,' 'need ≥ Z units'), (2) translate using key phrases: 'at most' → ≤, 'at least' → ≥, 'exactly' → =, 'more than' → >, 'less than' → <, (3) don't forget implicit constraints like x ≥ 0, y ≥ 0 (can't be negative) or x, y integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied (✓) or violated (✗). If all checks pass AND context is reasonable, mark VIABLE. If even one ✗ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!
A caterer is choosing trays of sandwiches and trays of fruit for an event. Let $x =$ number of sandwich trays and $y =$ number of fruit trays. Each sandwich tray serves 8 people and costs $\24$. Each fruit tray serves 6 people and costs $\18$. The caterer must serve at least 60 people and spend no more than $\180$. Trays must be whole numbers and nonnegative. Which constraint system matches the situation?
$$\begin{cases}24x+18y \ge 180\\8x+6y \ge 60\\x \ge 0,\\ y \ge 0\\x,y \in \mathbb{Z}\end{cases}$$
$$\begin{cases}24x+18y \le 180\\8x+6y \le 60\\x \ge 0,\\ y \ge 0\\x,y \in \mathbb{Z}\end{cases}$$
$$\begin{cases}24x+18y \le 180\\8x+6y \ge 60\\x \ge 0,\\ y \ge 0\\x,y \in \mathbb{Z}\end{cases}$$
$$\begin{cases}24x+18y \le 180\\8x+6y \ge 60\\x \le 0,\\ y \le 0\\x,y \in \mathbb{Z}\end{cases}$$
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. A constraint is a limitation or requirement: 'budget at most $500' becomes cost $ \le 500$, 'need at least 10 units' becomes quantity $ \ge 10$. The system of ALL constraints defines the feasible region—the set of all solutions that work. A solution is viable if it lies in this feasible region (satisfies every single inequality/equation) AND makes real-world sense (no negative quantities, whole units when needed, etc.). Even one violation makes it nonviable! The constraints are cost $24x + 18y \le 180$ (no more than $180), serving $8x + 6y \ge 60$ (at least 60 people), and $x \ge 0$, $y \ge 0$ with integers (nonnegative whole trays). Choice A correctly represents all constraints with $ \le $ for cost and $ \ge $ for serving, including nonnegativity and integers. A distractor like Choice B flips cost to $ \ge 180$, which means spending at least $180, but the limit is at most—remember to match 'no more than' to $ \le $! Constraint identification from context: (1) list every limitation mentioned ('budget $X,$ 'time $ \le $ Y hours,' 'need $ \ge $ Z units'), (2) translate using key phrases: 'at most' $ \to \le $, 'at least' $ \to \ge $, 'exactly' $ \to =$, 'more than' $ \to >$, 'less than' $ \to <$, (3) don't forget implicit constraints like $x \ge 0$, $y \ge 0$ (can't be negative) or $x, y$ integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied (✓) or violated (✗). If all checks pass AND context is reasonable, mark VIABLE. If even one ✗ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!
A small business runs two ad types: online ads and radio ads. Let $x$ = number of online ads and $y$ = number of radio ads.
Constraints:
- Each online ad costs $\$40$; each radio ad costs $$90$.
- Total ad budget is at most $\$900$.
- They want at least 8 total ads.
- At most 6 radio ads can be run.
- Nonnegativity: $x\ge 0,\ y\ge 0$.
Which system of inequalities represents the constraints?
$$\begin{cases}40x+90y\le 900\\x+y\le 8\\y\le 6\\x\ge 0,\\ y\ge 0\end{cases}$$
$$\begin{cases}40x+90y\le 900\\x+y\ge 8\\y\ge 6\\x\ge 0,\\ y\ge 0\end{cases}$$
$$\begin{cases}40x+90y\le 900\\x+y\ge 8\\y\le 6\\x\ge 0,\\ y\ge 0\end{cases}$$
$$\begin{cases}40x+90y\ge 900\\x+y\ge 8\\y\le 6\\x\ge 0,\\ y\ge 0\end{cases}$$
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. A constraint is a limitation or requirement: 'budget at most $500' becomes cost ≤ 500, 'need at least 10 units' becomes quantity ≥ 10. The system of ALL constraints defines the feasible region—the set of all solutions that work. A solution is viable if it lies in this feasible region (satisfies every single inequality/equation) AND makes real-world sense (no negative quantities, whole units when needed, etc.). Even one violation makes it nonviable! The constraints are cost 40x + 90y ≤ 900 (at most $900), total ads x + y ≥ 8 (at least 8), radio limit y ≤ 6, and nonnegativity x ≥ 0, y ≥ 0. Choice A correctly represents all constraints with the complete system, using the right directions for each. Choice D incorrectly uses y ≥ 6 for radio, but 'at most' is ≤, not requiring more. Constraint identification from context: (1) list every limitation mentioned ('budget $X,' 'time ≤ Y hours,' 'need ≥ Z units'), (2) translate using key phrases: 'at most' → ≤, 'at least' → ≥, 'exactly' → =, 'more than' → >, 'less than' → <, (3) don't forget implicit constraints like x ≥ 0, y ≥ 0 (can't be negative) or x, y integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied (✓) or violated (✗). If all checks pass AND context is reasonable, mark VIABLE. If even one ✗ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!
A rectangle is being designed for a poster. Let $L$ = length (in inches) and $W$ = width (in inches).
Constraints:
- Perimeter must be at most 40 inches.
- Area must be at least 75 square inches.
- Both dimensions must be positive: $L>0,\ W>0$.
Which system represents these constraints?
$$\begin{cases}2L+2W\le 40\\LW\ge 75\\L>0,\\ W>0\end{cases}$$
$$\begin{cases}L+W\le 40\\LW\ge 75\\L>0,\\ W>0\end{cases}$$
$$\begin{cases}2L+2W\ge 40\\LW\ge 75\\L>0,\\ W>0\end{cases}$$
$$\begin{cases}2L+2W\le 40\\LW\le 75\\L>0,\\ W>0\end{cases}$$
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. A constraint is a limitation or requirement: 'budget at most $500' becomes cost ≤ 500, 'need at least 10 units' becomes quantity ≥ 10. The system of ALL constraints defines the feasible region—the set of all solutions that work. A solution is viable if it lies in this feasible region (satisfies every single inequality/equation) AND makes real-world sense (no negative quantities, whole units when needed, etc.). Even one violation makes it nonviable! The constraints are perimeter 2L + 2W ≤ 40 (at most 40), area LW ≥ 75 (at least 75), and positivity L > 0, W > 0. Choice B correctly represents all constraints with the complete system, using ≤ for perimeter and ≥ for area. Choice A incorrectly uses ≥ for perimeter, but 'at most' means ≤, which would require too large a perimeter. Constraint identification from context: (1) list every limitation mentioned ('budget $X,' 'time ≤ Y hours,' 'need ≥ Z units'), (2) translate using key phrases: 'at most' → ≤, 'at least' → ≥, 'exactly' → =, 'more than' → >, 'less than' → <, (3) don't forget implicit constraints like x ≥ 0, y ≥ 0 (can't be negative) or x, y integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied (✓) or violated (✗). If all checks pass AND context is reasonable, mark VIABLE. If even one ✗ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!
A school club is ordering snacks for a movie night. Let $x$ = number of pizzas and $y$ = number of boxes of cookies.
Constraints:
- Each pizza costs $\$12$ and each cookie box costs $$5$.
- The club can spend at most $\$120$.
- They need at least 15 total items (pizzas + cookie boxes).
- They cannot order negative amounts.
Which system of inequalities represents all constraints?
$$\begin{cases}12x+5y\le 120\\x+y\le 15\\x\ge 0,\\ y\ge 0\end{cases}$$
$$\begin{cases}12x+5y\le 120\\x+y\ge 15\end{cases}$$
$$\begin{cases}12x+5y\ge 120\\x+y\ge 15\\x\ge 0,\\ y\ge 0\end{cases}$$
$$\begin{cases}12x+5y\le 120\\x+y\ge 15\\x\ge 0,\\ y\ge 0\end{cases}$$
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. A constraint is a limitation or requirement: 'budget at most $500' becomes cost ≤ 500, 'need at least 10 units' becomes quantity ≥ 10. The system of ALL constraints defines the feasible region—the set of all solutions that work. A solution is viable if it lies in this feasible region (satisfies every single inequality/equation) AND makes real-world sense (no negative quantities, whole units when needed, etc.). Even one violation makes it nonviable! The constraints are cost 12x + 5y ≤ 120 (at most $120), total items x + y ≥ 15 (at least 15), and nonnegativity x ≥ 0, y ≥ 0, forming the complete system. Choice B correctly represents all constraints with the complete system, including the correct direction for the budget inequality. Choice A incorrectly uses ≥ for the cost, but 'at most' translates to ≤, which would allow overspending. Constraint identification from context: (1) list every limitation mentioned ('budget $X,' 'time ≤ Y hours,' 'need ≥ Z units'), (2) translate using key phrases: 'at most' → ≤, 'at least' → ≥, 'exactly' → =, 'more than' → >, 'less than' → <, (3) don't forget implicit constraints like x ≥ 0, y ≥ 0 (can't be negative) or x, y integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied (✓) or violated (✗). If all checks pass AND context is reasonable, mark VIABLE. If even one ✗ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!
A theater is selling two types of tickets: adult and student. Let $a$ = number of adult tickets and $s$ = number of student tickets.
Constraints:
- The theater can seat at most 180 people: $a+s\le 180$.
- At least 40 student tickets must be sold: $s\ge 40$.
- Revenue goal: adult tickets are $\$15$ and student tickets are $$10$; total revenue must be at least $\$2200$.
- Nonnegativity: $a\ge 0,\ s\ge 0$.
Which of the following points is viable?
$(a,s)=(160,40)
$(a,s)=(120,50)
$(a,s)=(100,30)
$(a,s)=(150,35)
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. Checking viability is systematic: (1) write out each constraint, (2) substitute the proposed solution into each one, (3) verify each is satisfied (inequality holds, equation balances), (4) check context reasonableness (non-negative? integers if needed?). If everything passes, it's viable. If anything fails, it's nonviable—and you should identify WHICH constraint was violated. Complete checking means checking ALL constraints, not just some! Checking each: (120,50) seats 170 ≤ 180 (✓), s=50 ≥ 40 (✓), revenue 15(120)+10(50)=1800+500=2300 ≥ 2200 (✓); (100,30) s=30 < 40 (✗); (160,40) seats 200 > 180 (✗); (150,35) seats 185 > 180 (✗) and s=35 < 40 (✗)—only (120,50) works. Choice A correctly determines viability with complete system checking for all points. Choice B gently, but (100,30) violates minimum students, though others fail differently—always check all. Constraint identification from context: (1) list every limitation mentioned ('budget $X,' 'time ≤ Y hours,' 'need ≥ Z units'), (2) translate using key phrases: 'at most' → ≤, 'at least' → ≥, 'exactly' → =, 'more than' → >, 'less than' → <, (3) don't forget implicit constraints like x ≥ 0, y ≥ 0 (can't be negative) or x, y integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied (✓) or violated (✗). If all checks pass AND context is reasonable, mark VIABLE. If even one ✗ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!
A student is choosing smoothies. Let $x$ = number of protein smoothies and $y$ = number of fruit smoothies.
Constraints:
- Protein requirement: at least 30 g total. Protein smoothie has 12 g; fruit smoothie has 6 g.
- Calorie limit: at most 500 calories total. Protein smoothie has 220 cal; fruit smoothie has 140 cal.
- Nonnegativity: $x\ge 0,\ y\ge 0$.
Determine which constraint the point $(x,y)=(1,4)$ violates (if any).
It violates the calorie limit.
It violates nonnegativity.
It violates none of the constraints (it is feasible).
It violates the protein requirement.
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. Checking viability is systematic: (1) write out each constraint, (2) substitute the proposed solution into each one, (3) verify each is satisfied (inequality holds, equation balances), (4) check context reasonableness (non-negative? integers if needed?). If everything passes, it's viable. If anything fails, it's nonviable—and you should identify WHICH constraint was violated. Complete checking means checking ALL constraints, not just some! For (1,4), protein: 12(1) + 6(4) = 12 + 24 = 36 ≥ 30 (✓); calories: 220(1) + 140(4) = 220 + 560 = 780 ≤ 500? 780 > 500 (✗); nonnegativity: yes—so violates calories. Choice B correctly identifies the violated constraint with proper reasoning on the calorie check. Choice A gently, but it actually violates calories, as the substitution shows 780 > 500, so not protein. Constraint identification from context: (1) list every limitation mentioned ('budget $X,' 'time ≤ Y hours,' 'need ≥ Z units'), (2) translate using key phrases: 'at most' → ≤, 'at least' → ≥, 'exactly' → =, 'more than' → >, 'less than' → <, (3) don't forget implicit constraints like x ≥ 0, y ≥ 0 (can't be negative) or x, y integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied (✓) or violated (✗). If all checks pass AND context is reasonable, mark VIABLE. If even one ✗ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!
A community garden is planning crops. Let $c$ = acres of corn and $s$ = acres of soybeans.\n\nConstraints:\n- Total land available: at most 60 acres: $c+s\le 60$.\n- Water available: at most 100 acre-ft. Corn uses 2 acre-ft per acre; soybeans use 1.5 acre-ft per acre.\n- At least 10 acres of corn must be planted.\n- Nonnegativity: $c\ge 0$, $s\ge 0$.\n\nWhich system correctly represents all constraints?
$$\begin{cases}c+s\ge 60\\2c+1.5s\le 100\\c\ge 10\\c\ge 0,\\ s\ge 0\end{cases}$$
$$\begin{cases}c+s\le 60\\2c+1.5s\le 100\\c\le 10\\c\ge 0,\\ s\ge 0\end{cases}$$
$$\begin{cases}c+s\le 60\\2c+1.5s\le 100\\c\ge 10\\c\ge 0,\\ s\ge 0\end{cases}$$
$$\begin{cases}c+s\le 60\\2c+1.5s\ge 100\\c\ge 10\\c\ge 0,\\ s\ge 0\end{cases}$$
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. A constraint is a limitation or requirement: 'budget at most $500' becomes $cost \leq 500$, 'need at least 10 units' becomes $quantity \geq 10$. The system of ALL constraints defines the feasible region—the set of all solutions that work. A solution is viable if it lies in this feasible region (satisfies every single inequality/equation) AND makes real-world sense (no negative quantities, whole units when needed, etc.). Even one violation makes it nonviable! The constraints are land $c + s \leq 60$, water $2c + 1.5s \leq 100$, minimum corn $c \geq 10$, and nonnegativity $c \geq 0$, $s \geq 0$, matching the given details exactly. Choice A correctly represents all constraints with the complete system, using $\leq$ for both limited resources. Choice B incorrectly flips the land to $\geq$, but 'at most' means $\leq$, not requiring more land than available. Constraint identification from context: (1) list every limitation mentioned ('budget $X$,' 'time $\leq$ Y hours,' 'need $\geq$ Z units'), (2) translate using key phrases: 'at most' $\to \leq$, 'at least' $\to \geq$, 'exactly' $\to =$, 'more than' $\to >$, 'less than' $\to <$, (3) don't forget implicit constraints like $x \geq 0$, $y \geq 0$ (can't be negative) or $x$, $y$ integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied ($\checkmark$) or violated ($\times$). If all checks pass AND context is reasonable, mark VIABLE. If even one $\times$ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!
Consider the system of constraints
$$\begin{cases}2x+y \le 12 \\ x+2y \le 14 \\ x \ge 0 \\ y \ge 0 \end{cases}$$
Which point is nonviable (infeasible) for this system?
$(4,2)$
$(0,7)$
$(2,4)$
$(5,4)$
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. Checking viability is systematic: (1) write out each constraint, (2) substitute the proposed solution into each one, (3) verify each is satisfied (inequality holds, equation balances), (4) check context reasonableness (non-negative? integers if needed?). If everything passes, it's viable. If anything fails, it's nonviable—and you should identify WHICH constraint was violated. Complete checking means checking ALL constraints, not just some! Checking each: $(2,4)$ $2(2)+4=8 \le 12$ (✓), $2+2(4)=10 \le 14$ (✓); $(4,2)$ $2(4)+2=10 \le 12$ (✓), $4+2(2)=8 \le 14$ (✓); $(5,4)$ $2(5)+4=14>12$ (✗); $(0,7)$ $0+7=7 \le 12$ (✓), $0+2(7)=14 \le 14$ (✓)—only $(5,4)$ fails. Choice C correctly identifies the nonviable point with complete checking showing it violates $2x + y \le 12$. Choice A gently, but $(2,4)$ satisfies both inequalities, so it's viable—check substitutions carefully. Constraint identification from context: (1) list every limitation mentioned ('budget $X,$ 'time ≤ Y hours,' 'need ≥ Z units'), (2) translate using key phrases: 'at most' → ≤, 'at least' → ≥, 'exactly' → =, 'more than' → >, 'less than' → <, (3) don't forget implicit constraints like $x \ge 0$, $y \ge 0$ (can't be negative) or x, y integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied (✓) or violated (✗). If all checks pass AND context is reasonable, mark VIABLE. If even one ✗ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!
A student has a monthly streaming budget and time limit. Let $x$ = hours of Service A watched and $y$ = hours of Service B watched. Service A costs $\$2$ per hour and Service B costs $$1$ per hour. The student can spend at most $\$30$ and watch at most 25 hours total. The student also wants at least 8 hours of Service A. Which system represents the constraints?
$$\begin{cases}2x+y\le 30\\x+y\le 25\\x\ge 8\\x\ge 0,\\ y\ge 0\end{cases}$$
$$\begin{cases}2x+y\le 30\\x+y\le 25\\x\le 8\\x\ge 0,\\ y\ge 0\end{cases}$$
$$\begin{cases}2x+y\ge 30\\x+y\le 25\\x\ge 8\\x\ge 0,\\ y\ge 0\end{cases}$$
$$\begin{cases}2x+y\le 30\\x+y\ge 25\\x\ge 8\\x\ge 0,\\ y\ge 0\end{cases}$$
Explanation
This question tests your ability to translate real-world limitations into mathematical constraints (equations and inequalities) and determine whether potential solutions are viable—meaning they satisfy all constraints and make sense in context. A constraint is a limitation or requirement: 'budget at most $500' becomes cost ≤ 500, 'need at least 10 units' becomes quantity ≥ 10. The system of ALL constraints defines the feasible region—the set of all solutions that work. A solution is viable if it lies in this feasible region (satisfies every single inequality/equation) AND makes real-world sense (no negative quantities, whole units when needed, etc.). Even one violation makes it nonviable! The constraints are cost 2x + y ≤ 30 (at most $30), total x + y ≤ 25 (at most 25 hours), x ≥ 8 (at least 8 of A), and x ≥ 0, y ≥ 0 (nonnegative). Choice A correctly represents all constraints with ≤ for cost and total, and ≥ for minimum A. A distractor like Choice C flips total to ≥25, but it's at most 25—match 'at most' to ≤ and 'at least' to ≥ thoughtfully! Constraint identification from context: (1) list every limitation mentioned ('budget $X,' 'time ≤ Y hours,' 'need ≥ Z units'), (2) translate using key phrases: 'at most' → ≤, 'at least' → ≥, 'exactly' → =, 'more than' → >, 'less than' → <, (3) don't forget implicit constraints like x ≥ 0, y ≥ 0 (can't be negative) or x, y integers (if discrete), (4) write the complete system. Missing even one constraint can make you accept infeasible solutions! The viability checklist: Make a table with one row per constraint. For each constraint, substitute your point and mark whether it's satisfied (✓) or violated (✗). If all checks pass AND context is reasonable, mark VIABLE. If even one ✗ appears OR context is violated (like negative values or fractional items), mark NONVIABLE and note which constraint failed. This organized approach prevents missing checks and makes your reasoning clear. Thorough constraint checking is what separates good modeling from sloppy work!