Question

Pauline found the inverse of [9/7 4/3] to be [-3/7 4/-9]. Which calculations will confirm that his (or her) answer is correct? Select all that apply.

Answer 1

In this case, we'll have to carry out several steps to find the solution.

Step 01:

data:

matrix

Step 02:

inverse of a matrix:

$AA^{-1}=\begin{bmatrix}{9} & {4} \\ {7} & {3}\end{bmatrix}\begin{bmatrix}{-3} & {4} \\ {7} & -{9}\end{bmatrix}=\begin{bmatrix}{1} & {0} \\ {0} & {1}\end{bmatrix}$$A^{-1}A=\begin{bmatrix}{-3} & {4} \\ {7} & {-9}\end{bmatrix}\begin{bmatrix}{9} & {4} \\ {7} & {3}\end{bmatrix}=\begin{bmatrix}{1} & {0} \\ {0} & {1}\end{bmatrix}$

That is the full solution.