Write down the inverse of each of the following elementary matrices: (a) $\left(\begin{array}{ll}0 & 1 \\ 1 & 0\end{array}\right)$,
(b) $\left(\begin{array}{ll}1 & 0 \\ 5 & 1\end{array}\right)$,
(c) $\left(\begin{array}{rr}1 & -2 \\ 0 & 1\end{array}\right)$,
(d) $\left(\begin{array}{rrr}1 & 0 & 0 \\ 0 & 1 & -3 \\ 0 & 0 & 1\end{array}\right)$,
(e) $\left(\begin{array}{llll}1 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 \\ 0 & 6 & 1 & 0 \\ 0 & 0 & 0 & 1\end{array}\right)$,
(f) $\left(\begin{array}{llll}0 & 0 & 0 & 1 \\ 0 & 1 & 0 & 0 \\ 0 & 0 & 1 & 0 \\ 1 & 0 & 0 & 0\end{array}\right)$.