Answer
$$\left[ \begin {array}{cccccc} \frac{1}{5}&0\\
0&1\end {array} \right].$$
Work Step by Step
Since $ad-bc=(5)(1)-(0)(0)=5\neq 0$, then the matrix has inverse given by
$$ \frac{1}{5} \left[ \begin {array}{cccccc} 1&0\\
0&5\end {array} \right]=\left[ \begin {array}{cccccc} \frac{1}{5}&0\\
0&1\end {array} \right].$$
