Practice Test 5 - College Algebra

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

  1. A bookstore tracks monthly profit (USD): month 1: 1400, month 2: 1550, month 3: 1700, month 4: 1850, month 5: 2000. A linear model is used to predict profits for ordering stock. Let xx be month number and yy be profit. What does the slope represent in this context?
  2. Solve for xx and check for extraneous solutions: 4x=10.\sqrt{4x}=10.
  3. How can the change of base formula be used to rewrite log⁡1/2(8)\log_{1/2}(8) in terms of common logarithms?
  4. A student is solving the equation 2x−13−x+46=x−22\frac{2x-1}{3} - \frac{x+4}{6} = \frac{x-2}{2}. After finding a common denominator and combining fractions, what is the resulting equation before solving for xx?
  5. After simplifying x2+5x+6x2−x−6\frac{x^2 + 5x + 6}{x^2 - x - 6}, what is the domain of the resulting expression?
  6. The cost of producing xx items follows the linear function C(x)=15x+200C(x) = 15x + 200. A competing company has a cost function with the same fixed costs but a marginal cost that is $3 higher per item. What is the slope of the competing company's cost function?
  7. Consider the system of equations: 3x−2y=73x - 2y = 7 and x+4y=−1x + 4y = -1. When solving by substitution, if you solve the second equation for xx and substitute into the first equation, what equation in terms of yy do you obtain?
  8. Which of the following correctly applies the product rule to log⁡b(xy)\log_b(xy)?
  9. A student solving 7x+4y=267x + 4y = 26 and 5x−3y=135x - 3y = 13 by elimination makes an error and gets the solution (2,3)(2, 3). When checking this solution in the original equations, what will they discover?
  10. A function f(x)f(x) passes through the points (−3,7)(-3, 7) and (5,−1)(5, -1). If g(x)=f(x−2)+3g(x) = f(x - 2) + 3, what is the average rate of change of g(x)g(x) over the interval [−1,7][-1, 7]?
  11. How does rationalizing the denominator of 14+2\frac{1}{4+\sqrt{2}} change it to a single fraction? Give your answer in simplest form.
  12. Which of the following correctly identifies the property that allows us to conclude that if x+5=12x + 5 = 12, then x+5+(−5)=12+(−5)x + 5 + (-5) = 12 + (-5)?
  13. A relation RR is defined by the set of ordered pairs {(2,3),(4,5),(2,7),(6,9),(8,5)}\{(2, 3), (4, 5), (2, 7), (6, 9), (8, 5)\}. Which statement best describes why this relation fails to be a function?
  14. Given that a=2xa = 2^x and b=3xb = 3^x, express 6x+6x+16^x + 6^{x+1} in terms of aa and bb.
  15. Which shows 30x2−45x30x^2-45x factored completely by its GCF?
  16. A savings account uses A(t)=2500(1.05)tA(t)=2500(1.05)^t; what happens if the initial amount is doubled?
  17. An account grows by 7% yearly from PP; which base correctly represents the growth factor?
  18. Consider the polynomial function f(x)=(x+2)3(x−1)2(x−4)f(x) = (x + 2)^3(x - 1)^2(x - 4). Which statement best describes the behavior of the graph at x=−2x = -2?
  19. The graph of y=f(x)y = f(x) passes through the point (3,−2)(3, -2). After applying the transformation y=2f(x−1)+3y = 2f(x-1) + 3, through which point does the new graph pass?
  20. The equation kx2+8x+k=0kx^2 + 8x + k = 0 has real solutions when the discriminant is non-negative. For which values of kk does this equation have real solutions?

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