Chapter 1.6, Problem 18E

Consider the matrices

$A=\left[\begin{array}{l}212\\ 22-2\\ 311\end{array}\right]$ and $x=\left[\begin{array}{l}{x}_1\\ x_2\\ x_3\end{array}\right]$

1. a. Show that the equation Ax = x can be rewritten as (A − I)x = 0 and use this result to solve Ax = x for x.
2. b. Solve Ax = 4x.