Practice Test 17 - Algebra 1

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

  1. A sequence is defined by h(1)=4h(1) = 4 and h(n+1)=12h(n)+6h(n+1) = \frac{1}{2}h(n) + 6 for n≥1n \geq 1. If this pattern continues indefinitely, what value does h(n)h(n) approach as nn becomes very large?
  2. The ideal gas law is PV=nRTPV = nRT, where PP is pressure, VV is volume, nn is the number of moles, RR is the gas constant, and TT is temperature. A chemist needs to find the number of moles when pressure decreases by half and volume doubles, while temperature remains constant. If the original number of moles was n0n_0, what is the new number of moles?
  3. If R(x)=x3−2x+5R(x) = x^3 - 2x + 5 and S(x)=3x2+x−4S(x) = 3x^2 + x - 4, which expression represents R(x)−S(x)R(x) - S(x)?
  4. A streaming service charges according to C=8n+20C = 8n + 20, where CC is the total cost (in dollars) and nn is the number of months. What does it mean that the y-intercept is 20?
  5. The value of a laptop over time is shown by V(t)=1200(0.90)tV(t)=1200(0.90)^t, where tt is the number of years since purchase. Identify the constant percent change per year.
  6. How many real solutions (intersection points) does the linear-quadratic system have? {y=x+3y=x2+2x+5\begin{cases} y = x + 3 \\ y = x^2 + 2x + 5 \end{cases}
  7. Solve for xx: 2x−14=3\frac{2x - 1}{4} = 3
  8. In the perimeter formula for a rectangle, P=2l+2wP = 2l + 2w, solve for the length ll in terms of PP and ww.
  9. A gym charges a membership fee plus a fixed cost per visit. The total cost CC (in dollars) after vv visits is C=25+4vC = 25 + 4v. Is the rate of change of cost with respect to visits constant? If so, what is the rate?
  10. A gasoline container holds 3.5 gallons. Convert this to liters. (Use 1 gal=3.785 L1\text{ gal}=3.785\text{ L}.)
  11. A taxi charges a $4 starting fee plus $2 per mile. Let mm be miles traveled and CC be total cost (in dollars). Which equation represents this relationship?
  12. A bank account balance is modeled by A(t)=1000(1.01)12tA(t)=1000(1.01)^{12t}, where tt is in years. What is the monthly interest rate?
  13. Solve by completing the square: x2+2x+5=0x^2+2x+5=0. What are the solutions?
  14. Solve using elimination: {2x+3y=122x−y=4\begin{cases} 2x + 3y = 12 \\ 2x - y = 4 \end{cases} What is the solution (x,y)(x, y)?
  15. Consider g(x)=x4g(x)=x^4 (polynomial) and h(x)=2xh(x)=2^x (exponential). Which statement best describes what happens as xx gets large?
  16. Let f(x)=x−4f(x)=x-4 and g(x)=x2g(x)=x^2. Evaluate f(g(−3))f(g(-3)).
  17. Verify by multiplying back that the following rewriting is correct. Which expression equals x2+6x−1\frac{x^2 + 6}{x - 1} in the form q(x)+r(x)x−1q(x) + \frac{r(x)}{x - 1} with deg⁡(r)<1\deg(r) < 1?
  18. The graph shows the temperature TT (in degrees Fahrenheit) as a function of time hh (in hours after midnight). Estimate the average rate of change in temperature from 6 AM to 2 PM.
  19. An exponential function has initial value a=6a = 6 and triples each time xx increases by 1. Write the function in the form y=a⋅bxy = a \cdot b^x.​​​
  20. For f(x)=xf(x)=\sqrt{x} and g(x)=x+15g(x)=x+15, evaluate f(g(1))f(g(1)).​

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