Working with Functions

The math part of the ACT test will have several questions on functions.

Learn how to solve function questions with our free exercises.

Try the following question on functions.

Functions – Sample Question

Table of values for the functions f1(x) and f2(x) are given below.

What is the value of f2(f1(1))?

x f1(x) x f2(x)
1 4 1 1
2 5 2 4
3 6 3 9
4 7 4 16

A. 1

B. 4

C. 7

D. 9

E. 16

The correct answer is E.

Function problems will often include a table like the one provided above.

In order to solve the function, you need to look at the corresponding value in the table.

So, for example, the value of f1(2) from the table above is 5.

To solve the problem, you just have to look at the row for the number 2 and find the value in the second column of the table for f1.

So first of all, solve for the function in the inner-most set of parentheses, which in this problem is f1(1).

According to the table of values at the left above, for x = 1, f1(1) = 4

Then, take this new value to solve for f2(x)

According to the table of values at the right above, for x = 4, f2(4) = 16

More Algebra Questions

Free Sample Test