SAT Math Question of the Day

Math Category: Functions:

Q: If f(x) = x2 - 3, then f(2a) =

  1. 2a - 3
  2. 2x - 3
  3. 2x2 - 3
  4. 2a2 - 3
  5. 4a2 - 3

UNANSWERED.

The correct answer is E.

A: The correct answer is 4a2 - 3.

Substitute 2a wherever the x occurs in the equation:
f(x) = x2 - 3
f(2a) = (2a)2 - 3
f(2a) = 4a2 - 3