Practice Test 16 - Algebra 1

20 questions. Answer them in any order, then submit to see your score and every explanation.

  1. Solve algebraically (using substitution) and identify the intersection point(s) of the line and parabola: {\ny=2x+1\ny=x2+1\n\begin{cases}\n y = 2x + 1 \\ \n y = x^2 + 1\n\end{cases}
  2. An investment changes from $800 to $840 in one year and then to $882 in the next year. Does this represent constant percent growth, and if so, what is the percent rate per year?
  3. Which set represents the domain of the function f(x)=x+1x2−9f(x)=\dfrac{x+1}{x^2-9}? Give your answer in interval notation.
  4. Factor q(x)=x2+2x−15q(x)=x^2+2x-15 to find the zeros and the axis of symmetry.
  5. A recursive formula for a sequence is given as a1=7a_1 = 7 and an=an−1+4a_n = a_{n-1} + 4 for n≥2n \geq 2. Which explicit formula represents the same sequence and what is the value of a15a_{15}?
  6. What is the common difference dd of the arithmetic sequence 15,11,7,3,…15, 11, 7, 3, \dots?
  7. A car's distance from home (in miles) after tt hours is d(t)=50t+20d(t)=50t+20. What is the average rate of change of d(t)d(t) from t=1t=1 to t=4t=4, and what are the units?
  8. A student solving x2+x3=5\frac{x}{2} + \frac{x}{3} = 5 decides to multiply the entire equation by 6. When asked to justify this choice, which explanation demonstrates the best mathematical reasoning?
  9. The function f(x)=3(x−1)(x+3)f(x)=3(x-1)(x+3) is in factored form. What does this reveal about the graph?
  10. A balance is modeled by (1.20)t(1.20)^t for tt years (20% annual growth). Which is an equivalent form that highlights the approximate monthly growth factor?
  11. A school fundraiser sells bracelets for $5 each and charges a one-time $10 setup fee for the order. Let bb be the number of bracelets and let CC be the total cost (in dollars). What equation represents the relationship between CC and bb?​
  12. How many solutions does the system have? {2x+4y=10x+2y=5\begin{cases} 2x+4y=10 \\ x+2y=5 \end{cases}​
  13. A medication amount in the bloodstream decreases by 20% every hour. Which function represents the amount A(t)A(t) after tt hours if A(0)=80A(0)=80 mg?
  14. A rational expression P(x)x2+4\frac{P(x)}{x^2 + 4} is rewritten as x2−4+3x+12x2+4x^2 - 4 + \frac{3x + 12}{x^2 + 4}. What is P(2)P(2)?
  15. The cost (in dollars) to rent a bike is given by C=3h+8C=3h+8, where hh is the number of hours. What is the constant term in 3h+83h+8?
  16. A pet shelter is buying bags of dog food and cat food. Let xx be the number of dog-food bags and yy be the number of cat-food bags. - Dog food costs $18 per bag and cat food costs $12 per bag. Budget is at most $240: 18x+12y≤24018x+12y\le 240. - Storage space allows at most 20 bags total: x+y≤20x+y\le 20. - They need at least 6 dog-food bags: x≥6x\ge 6. - x≥0x\ge 0 and y≥0y\ge 0. Check whether (x,y)=(6,12)(x,y)=(6,12) satisfies all constraints.
  17. On a coordinate plane, graph y=x2+4x+3y=x^2+4x+3. What are the xx-intercepts (as points)?
  18. Verify that the definition 82/3=(81/3)28^{2/3}=(8^{1/3})^2 is consistent with exponent properties. Which explanation uses exponent rules correctly (not just computation)?
  19. Given g(x)=x−(2x−1)g(x) = x - (2x - 1), evaluate g(4)g(4).
  20. Determine whether the function g(x)=x2+2xg(x) = x^2 + 2x has a constant rate of change.

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