16Hit1600
AlgebraVery hardEvaluating a shifted function

Algebra practice question

The functions f and g are defined by f(x) = 2x + 1 and g(x) = f(x − 3). What is the value of g(5)?

Answer: 5

g(5) = f(5 − 3) = f(2) = 2(2) + 1 = 5.

Common wrong answers

If you answered 8
8 is f(5) − 3 = 11 − 3 — subtracting 3 from the OUTPUT instead of the input.
If you answered 11
11 is f(5); the shift means f is evaluated at 5 − 3 = 2.
If you answered 17
17 is f(8), adding 3 to the input instead of subtracting it.

More Algebra questions

Not affiliated with the College Board. SAT is a trademark of the College Board.