Answer
See below.
Work Step by Step
We see that the left hand side of the graph corresponds to the line with a slope of $\frac{-1}{1}=-1$ and an y-intercept of $0$, which implies the line of $y=-x$.
We can also see that the right side of the graph corresponds to a line with slope of $\frac{1}{2}=0.5 $ and y-intercept of $0$, which is $y=0.5x$. So our equation is:
$f(x)=-x$ if $-1\leq x\leq0$ and $f(x)=0.5x$ if $0\leq x\leq1$
