# Function

Author: mathforces
Problem has been solved: 192 times

Русский язык | English Language

For some continious function $f:R->R$ it is given that $9f(x+y)=f(x)f(y)$, for all real numbers $x$ and $y$. What is the value of $f(-f(1))$, if $f(1)=3?$