HOW $DO$ I READ THESE GRAPHS? Step $by$ Step explanations please

$10>12$Match each graph with its equation.

$f(x,y)=x^2+y^2$

$f(x,y)=sin(x)$

$f(x,y)=y^2$

$f(x,y)=\frac{1}{1+x^2+y^2}$

$f(x,y)=(x-y{)}^2$