Practice Domain in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The domain of a function is the complete set of allowable input values for which the function produces a defined, valid output.

The domain is the list of valid "questions" you can ask the function โ€” values outside the domain produce undefined or meaningless answers.

Showing a random 20 of 50 problems.

Example 1

easy
Find the domain of f(x)=3xโˆ’5f(x) = 3x - 5.

Example 2

easy
Find the domain of f(x)=3x2+1f(x) = \dfrac{3}{x^2 + 1}.

Example 3

hard
Find the domain of f(x)=x2โˆ’5x+6f(x) = \sqrt{x^2 - 5x + 6}.

Example 4

hard
For what values of kk does f(x)=x2+kx+1f(x) = \sqrt{x^2 + kx + 1} have domain all reals?

Example 5

easy
Find the domain of f(x)=x+1xโˆ’1f(x)=\sqrt{x}+\frac{1}{x-1}.

Example 6

challenge
Find the domain of f(x)=xโˆ’1x+2f(x)=\sqrt{\frac{x-1}{x+2}}.

Example 7

easy
Find the domain of f(x)=1(x+1)(xโˆ’2)f(x) = \dfrac{1}{(x+1)(x-2)}.

Example 8

easy
Find the domain of f(x)=5xf(x)=\frac{5}{x}.

Example 9

medium
Find the domain of f(x)=logโก2(2xโˆ’6)f(x)=\log_2(2x-6).

Example 10

medium
Find the domain of f(x)=logโก(x2โˆ’9)f(x) = \log(x^2 - 9).

Example 11

medium
Find the domain of f(x)=1xโˆ’4f(x) = \dfrac{1}{\sqrt{x - 4}}.

Example 12

easy
Find the domain of f(x)=2x+7f(x)=2x+7.

Example 13

medium
Find the domain of f(x)=xโˆ’1x2โˆ’xf(x)=\frac{x-1}{x^2-x}.

Example 14

easy
Find the domain of f(x)=x2โˆ’4x+1f(x)=x^2-4x+1.

Example 15

medium
Find the domain of f(x)=x+5โˆ’xf(x) = \sqrt{x} + \sqrt{5 - x}.

Example 16

medium
Find the domain of h(x)=x+1xโˆ’5h(x) = \frac{\sqrt{x + 1}}{x - 5}.

Example 17

challenge
Find the domain of f(x)=x+35โˆ’xf(x)=\frac{\sqrt{x+3}}{\sqrt{5-x}}.

Example 18

medium
Find the domain of f(x)=logโก(xโˆ’1)+logโก(7โˆ’x)f(x)=\log(x-1)+\log(7-x).

Example 19

easy
Find the domain of f(x)=xโˆ’13f(x) = \sqrt[3]{x - 1}.

Example 20

medium
Find the domain of f(x)=16โˆ’x2f(x) = \sqrt{16 - x^2}.