Answer
FALSE.
Work Step by Step
Take $$f(x,y)= \frac{x}{y}$$,
Now $$f(ax,ay)=\frac{ax}{ay}= \frac{x}{y}=f(x,y)$$.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.