Question 1 of 3Easy
If f(x) = 2x + 7, what is f(4)?
- 8
- 11
- 15
- 22
Show answer and solution
Correct answerC. 15
Solution walkthrough
- Substitute 4 for x: f(4) = 2(4) + 7 = 15.
SAT Math skill page
Read f(x) as a rule: plug in the input carefully, then answer what the output means.
What this tests
Dolphin question bank
Avoid these traps
Function notation names the output produced by input x; it does not mean f times x.
The input must replace every occurrence of the function variable, with parentheses when needed.
Study plan
Related practice
Skill cluster
FAQ
It is the output of function f when the input is 3.
Both can represent the output of a function; f(x) additionally identifies the function and its input.