Correct. Find the range of the function, using all the output values for the function, which are known. The range is all the y-coordinates.

Range: $\displaystyle{\left\lbrace-{8},-{1},{2},{5},{9}\right\rbrace}\usepackage{cmbright}\Huge\$

Because the domain has the same set of numbers as the range, you can find the number missing from the set of input values, or x-coordinates.

Domain: $\displaystyle{\left\lbrace?,-{8},-{1},{2},{9}\right\rbrace}\usepackage{cmbright}\Huge\$

The missing value in the function is 5.