SAT Math Question of the Day

Math Category: Functions:

Q: If f(x) = x2 + 2x - 1, then f(4) =

  1. 0
  2. 8
  3. 15
  4. 23
  5. 25

UNANSWERED.

The correct answer is D.

A: 23 is the correct answer. To solve this function problem, plug in the number 4 wherever the x occurs.
f(x) = x2 + 2x - 1
f(4) = 42 + 2(4) - 1
     = 16 + 8 - 1
     = 23