Answer
$\left[\begin{array}{rrr}
{-13}&{7}&{-12}\\
{-18}&{10}&{-14}\\
{17}&{-7}&{34}\end{array}\right]$
Work Step by Step
$CA=\left[\begin{array}{ccc}
{1}&{14}&{-14}\\
{2}&{22}&{-18}\\
{3}&{0}&{28}\end{array}\right]\quad$(see sol. exercise 17)
$CB=\left[\begin{array}{ccc}
{14}&{7}&{-2}\\
{20}&{12}&{-4}\\
{-14}&{7}&{-6}\end{array}\right]\quad$(see sol. exercise 18)
Both are 3 by 3 matrices, so the difference is defined.
$CA-CB=\left[\begin{array}{ccc}
{1-14}&{14-7}&{-14-(-2)}\\
{2-20}&{22-12}&{-18-(-4)}\\
{3-(-14)}&{0-7}&{28-(-6)}\end{array}\right]$
$=\left[\begin{array}{rrr}
{-13}&{7}&{-12}\\
{-18}&{10}&{-14}\\
{17}&{-7}&{34}\end{array}\right]$
