16Hit1600
AlgebraHardChecking values against a linear function defined by slope and a point

Algebra practice question

A linear function f has a slope of −2, and f(3) = 10. Which of the following must be true?

  1. A. f(8) = 0Correct
  2. B. f(0) = 10
  3. C. f(4) = 10
  4. D. f(−2) = 12

Answer: A. f(8) = 0

From f(3) = 10 with slope −2: f(x) = −2(x − 3) + 10 = −2x + 16. Then f(8) = −16 + 16 = 0.

Why the other answers are wrong

B. f(0) = 10
f(0) = 16, the y-intercept, not 10.
C. f(4) = 10
f(4) = 8: one step right lowers the value by 2.
D. f(−2) = 12
f(−2) = 20.

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