If $$A = \begin{bmatrix}1 & 1 \\ -1 & 2 \end{bmatrix}$$ then $$A^{-1} = \begin{bmatrix}a & b \\ c & d \end{bmatrix}$$ where
$a =$
$b =$
$c =$
$d =$
Use it to solve the linear system $$\begin{array}{rcl} x+y &=& 1 \\ -x+2y &=& 2 \\ \end{array}$$ $x =$
$y =$