Practice Test 38 - Algebra 2

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

  1. The system {ax+2y=63x+by=9\begin{cases} ax + 2y = 6 \\ 3x + by = 9 \end{cases} has solution (2,1)(2, 1). If the system {ax+2y=123x+by=18\begin{cases} ax + 2y = 12 \\ 3x + by = 18 \end{cases} is formed by doubling the right sides, what is the solution to this new system?
  2. A car rental company charges $45 per day plus a one-time fee of $30. You have at most $300 to spend. Create an inequality and find the maximum whole number of days you can rent the car. Let dd = number of days.
  3. Order the following functions by eventual growth rate (from greatest to least) as x→∞x\to\infty:   f(x)=0.1⋅3x\;f(x)=0.1\cdot 3^x (exponential),   g(x)=x6\;g(x)=x^6 (polynomial),   h(x)=50x2\;h(x)=50x^2 (quadratic),   p(x)=100x\;p(x)=100x (linear).
  4. Factor s(x)=4x2−9s(x)=4x^2-9 to reveal its zeros. Then identify the x-intercepts of the graph of y=s(x)y=s(x).
  5. Determine whether the system has no solution, one solution, or infinitely many solutions: {2x+y=64x+2y=12\begin{cases} 2x + y = 6\\ 4x + 2y = 12 \end{cases}
  6. Sketch f(x)=x+2x−1f(x)=\frac{x+2}{x-1} showing all asymptotes and intercepts. Which set of features is correct?
  7. Simplify. This uses multiplication of rational expressions (factor, cancel, multiply), demonstrating closure under multiplication. x2+5x+6x2−9⋅x−3x+2\displaystyle \frac{x^2+5x+6}{x^2-9}\cdot\frac{x-3}{x+2}
  8. What is the equation of a circle centered at (−2,5)(-2,5) with radius 77? (Use the distance formula idea that every point on the circle is 77 units from the center.)
  9. A science sensor records the temperature change according to T(t)=18+2.5tT(t)=18+2.5t, where tt is time in minutes since the start of an experiment. The experiment runs from t=0t=0 to t=40t=40 minutes. What is the realistic domain for tt?
  10. The complex number w=−2+23iw = -2 + 2\sqrt{3}i has modulus 44 and argument 120°120°. What is the result of w3w^3 expressed in rectangular form?
  11. Add the polynomials (combine like terms). The sum should be a polynomial by closure under addition: (4x3−2x2+6)+(−x3+5x−9).(4x^3-2x^2+6)+( -x^3+5x-9).
  12. Use logarithms to solve for xx: 2⋅10x/3=192\cdot 10^{x/3}=19. Express the solution as a logarithm and approximate using a calculator.
  13. Graph p(x)=2(x−1)2(x+2)3p(x)=2(x-1)^2(x+2)^3 showing zeros with multiplicities, whether the graph crosses or touches at each zero, and the correct end behavior. (Rough sketch.)​
  14. Divide x3−1x^3-1 by x−1x-1 and express x3−1x−1\frac{x^3-1}{x-1} in the form q(x)+rx−1q(x)+\frac{r}{x-1}, where deg⁡(r)<deg⁡(x−1)\deg(r)<\deg(x-1).
  15. Rewrite the exponential equation 103=100010^3 = 1000 in logarithmic form (use the common logarithm base 1010).
  16. Given the graph of f(x)=x2f(x)=x^2 and the graph of g(x)=f(x)+kg(x)=f(x)+k shown, the vertex of gg is at (0,−3)(0,-3). What is kk?
  17. A lab culture starts with 50 cells and grows by 20% each day. Create an exponential model for the number of cells after tt days, then solve for how many days it takes to reach 500 cells. Round to the nearest tenth of a day and interpret your result in context.
  18. Which statement about long-term growth is true for the functions f(x)=100x2f(x)=100x^2 (quadratic) and g(x)=1.2xg(x)=1.2^x (exponential)?​
  19. A town has an initial population of 12,000 and grows by 3% each year. Create an exponential model for the population after tt years, then determine how many years it will take for the population to reach 15,000. Round to the nearest tenth of a year and interpret your result in context.
  20. After restricting f(x)=(x−4)2f(x)=(x-4)^2 to the domain x≤4x\le 4 so that it is one-to-one, what is the inverse function f−1(x)f^{-1}(x)?

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