Chapter 4.2, Problem 21E

In Problems $19\text{-}22$, write the system of linear equations that is represented by the given augmented matrix. Assume that the variables are $x_1$ and $x_2$.

$\left.\left[\left.\begin{array}{cc}4& 0\\ 0& 8\end{array}\right|\right.\begin{array}{c}-10\\ 40\end{array}\right]$