Question

determine whether the following equation defines y as a function of x.
x + y = 24
does the equation x + y = 24 define y as a function of x?
yes
no

Explanation:

Step1: Rearrange for y in terms of x

$y = 24 - x$

Step2: Check single y per x

For every $x$, only one $y$ exists.

Answer:

Yes