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Math: Functions Flashcards

7 cards from real ACT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. If f(x) = 3x - 5, what is f(4)?

    Answer: 7

    f(4) = 3(4) - 5 = 12 - 5 = 7.

  2. If g(x) = x^2 + 2x, what is g(-3)?

    Answer: 3

    g(-3) = (-3)^2 + 2(-3) = 9 - 6 = 3.

  3. What is the domain of f(x) = 1/(x - 2)?

    Answer: All real numbers except 2

    The denominator cannot be zero, so x cannot equal 2.

  4. If f(x) = 2x + 1 and g(x) = x - 3, what is f(g(5))?

    Answer: 5

    g(5) = 2, then f(2) = 2(2) + 1 = 5.

  5. Which value of x makes f(x) = x^2 - 9 equal to zero?

    Answer: 3

    x^2 - 9 = 0 gives x = 3 or x = -3, so 3 is a solution.

  6. What is the slope of the linear function f(x) = -4x + 7?

    Answer: -4

    In y = mx + b form, the coefficient of x is the slope, which is -4.

  7. If h(x) = x^2, what is h(x + 1)?

    Answer: x^2 + 2x + 1

    h(x + 1) = (x + 1)^2 = x^2 + 2x + 1.