$12.$ Use Green$$s theorem to evaluate the integral I

$$R

y

$2$

dx$+$xdy$,$ where

$($a$)$ R is the square with vertices $(0,0),(2,0),(2,2),(0,2).$

$($b$)$ R is the square with vertices $(1,1).$

$($c$)$ R is the disc of radius $2$ and center $(0,0)($specify the orientation you use for the

curve.$)$