Use Row Reduction to Find the Inverse of the Given $\left[ \begin{array} { l l } 2 & 1 \\1 & 1\end{array} \right]$

Essay

Use row reduction to find the inverse of the given matrix, if it exists, and check your answer by multiplication.
​ $\left[ \begin{array} { l l } 2 & 1 \\1 & 1\end{array} \right]$