Find the inverse of the matrix (if it exists): $ \begin{bmatrix} 1&2&3 \\ 0&2&4 \\ 0&0&5 \\ \end{bmatrix} $

Question

$\begin{array}{1 1} \frac{-1}{10}\begin{bmatrix}10 & -10 & 2\\0 & 5 & -4\\0 & 0 & 2\end{bmatrix} \\\frac{1}{10}\begin{bmatrix}10 & -10 & 2\\0 & 5 & -4\\0 & 0 & 2\end{bmatrix} \\ 10\begin{bmatrix}10 & -10 & 2\\0 & 5 & -4\\0 & 0 & 2\end{bmatrix} \\ -10\begin{bmatrix}10 & -10 & 2\\0 & 5 & -4\\0 & 0 & 2\end{bmatrix} \end{array} $