Does the graph of $y + |y| = x + |x|$ represent a function of $x$? The question is whether or not the graph $y + |y| = x + |x|$ represents a function of $x$. Explain why.
It looks like a weird graph but it would probably be a function because if you say $f(x) = y$ (you get a $y$ value)?

It is a function only if for every $x$ you only have one $y$ value satisfying the equation. 
Now look for example the value $x=-1$ and $y=-1$ or $x=-1$ and $y=0$.
