Assume $A$ is an upper triangular matrix and $X$ is a matrix such that $AX = I$, where $I$ is the identity matrix. Since $A$ is upper triangular, it has the form:
\[ A = \begin{bmatrix}
a_{11} & a_{12} & \cdots & a_{1n} \\
0 & a_{22} & \cdots & a_{2n} \\
\vdots &
Show more…