## Precalculus (6th Edition) Blitzer

The value of $\left( f\circ f \right)\left( -4 \right)$ is $0$.
We know that the function $\left( f\circ f \right)\left( x \right)=\left( f\left( f\left( x \right) \right) \right)$ So, $\left( f\circ f \right)\left( -4 \right)=f\left( f\left( -4 \right) \right)$ First of all, find the value of $f\left( -4 \right)$ from the graph that is $f\left( -4 \right)=0$. Then, $f\left( f\left( -4 \right) \right)=f\left( 0 \right)$ So, from the graph, one can see $f\left( 0 \right)=0$ Thus, the value of $\left( f\circ f \right)\left( -4 \right)$ is $0$.