Q: joint density $P(x, y)$ when $Y=X^2+Z$ and $X, Z$ are uniformly distributed.

Question

$Y=X^2+Z$, $X$ and $Z$ are uniformly distributed. $$ P(x)=\frac12 I_{\{-1<x<1\}}, \\ P(z)=10 I_{\{0<z<1/10\}}\\ P(x,y)={}? $$ How can I solve it?

**X and Z are independent