Let $$A=\left(\begin{array}{cc} 3 & 6 \cr -3 & 8 \end{array}\right)$$ Then $$A^{-1}=\left(\begin{array}{cc} a_{11} & a_{12} \cr a_{21} & a_{22} \end{array}\right)$$ where $a_{11}=$ , $a_{12}=$ , $a_{21}=$ , $a_{22}=$ .