Find the difference of these matrices. If it's impossible, type "impossible".



$\begin{array}{l}

A=\left[\begin{array}{c}

-3 \\

8

\end{array}\right] \\

B=\left[\begin{array}{c}

-12 \\

-4

\end{array}\right]

\end{array}$



$A-B=\left[\begin{array}{l}

? \\

?

\end{array}\right]$