If you enjoy solving functions (and why wouldn't you?), then you'll have a great time on the Praxis Core exam. The following practice questions will help you put the
fun into "function" by asking you to first solve a simple function, and then to find the value of two functions combined!
Practice questions
- If f(x) = x – 2, what is the value of f(3)?
A. 1
B. 4
C. 3
D. 0
E. 2
- For the two following functions, what is the value of f(g(1))?
f(x) = 8x2 – 2x + 12
g(x) = 3x + 5
A. 508
B. 415
C. 29
D. 580
E. 18
Answers and explanations
- The correct answer is Choice (A).
Because f(3) replaces the x in f(x) with 3, put 3 in for x in x – 2:

- The correct answer is Choice (A).
First, find the value of g(1):

Because g(1) is 8, f(g(1)) is f(8):

Therefore, f(g(1)) is 508, Choice (A).