Practice Test 4 - College Algebra

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

  1. If 2x2+kx+182x^2 + kx + 18 can be factored as (2x+a)(x+b)(2x + a)(x + b) where aa and bb are integers, what is the value of kk?
  2. How can the change of base formula be used to rewrite log⁡3(81)\log_3(81) in terms of natural logarithms?
  3. The function g(x)=ax3+bx2+cx+dx2−4g(x) = \frac{ax^3 + bx^2 + cx + d}{x^2 - 4} has a slant asymptote with equation y=3x+2y = 3x + 2. If the function has a vertical asymptote at x=2x = 2 but not at x=−2x = -2, what must be true about the coefficients?
  4. Simplify x3−8x2+2x+4÷x2−4x2+4x+4\frac{x^3-8}{x^2+2x+4} \div \frac{x^2-4}{x^2+4x+4}.
  5. If log⁡b(x)=m\log_b(x)=m and log⁡b(y)=n\log_b(y)=n, what is log⁡b ⁣(xy)\log_b\!\left(\frac{x}{y}\right)?
  6. A ball is thrown upward from the top of a 96-foot building with an initial velocity of 80 feet per second. The height hh (in feet) is given by h(t)=−16t2+80t+96h(t) = -16t^2 + 80t + 96. How long does it take for the ball to reach its maximum height, and when does it hit the ground?
  7. A student wants to evaluate log⁡0.5(8)\log_{0.5}(8) using a calculator that only has base-10 logarithms. After applying the change of base formula correctly, which numerical calculation should be performed?
  8. Which of the following correctly applies the product rule to log⁡b(7x)\log_b(7x)?
  9. A polynomial function f(x)f(x) of degree 7 has the property that f′(x)=0f'(x) = 0 has exactly 4 real solutions. If f(x)f(x) has leading coefficient 3, which statement best describes the behavior and characteristics of f(x)f(x)?
  10. Recipe: solve x2+13=56\frac{x}{2}+\frac{1}{3}=\frac{5}{6} for xx cups.
  11. How can log⁡b ⁣((x2)5)\log_b\!\left((x^2)^5\right) be rewritten using the power rule?
  12. A student claims that f(x)=x4+2x3−5x2+13x4−x3+7x−2f(x) = \frac{x^4 + 2x^3 - 5x^2 + 1}{3x^4 - x^3 + 7x - 2} has a horizontal asymptote at y=13y = \frac{1}{3} because both the numerator and denominator have degree 4, so the horizontal asymptote equals the ratio of leading coefficients. Which analysis of this claim is correct?
  13. Budgeting: Solve 7x−14<217x-14<21 for weekly transport cost; express solution in interval notation.
  14. If log⁡a(x)=3.2\log_a(x) = 3.2 and log⁡b(x)=4.8\log_b(x) = 4.8, what is the value of log⁡a(b)\log_a(b) expressed in terms of these given values?
  15. Cost sharing: solve x6+112=512\frac{x}{6}+\frac{1}{12}=\frac{5}{12} dollars for xx.
  16. The rational function p(x)=−2x5+3x3+x4x5−x4+7x2−3p(x) = \frac{-2x^5 + 3x^3 + x}{4x^5 - x^4 + 7x^2 - 3} has end behavior that can be described as approaching which horizontal asymptote?
  17. A retirement account currently has 85,00085,000 and earns 6.3%6.3\% annual interest compounded quarterly. If no additional contributions are made, what will be the account balance when it reaches 200,000200,000?
  18. A bacteria culture starts with 500 bacteria and doubles every 3 hours. At the same time, due to environmental factors, 50 bacteria die every hour regardless of the population size. Which equation best models the bacteria population PP after tt hours?
  19. Which option correctly simplifies log⁡b ⁣(5xy)\log_b\!\left(\frac{5x}{y}\right)?
  20. Budgeting: Solve 12≤3x+612\le 3x+6 for minimum deposit; express solution in interval notation.

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