#### Answer

The matrix is represented by:
x + 2y - 2z = -1
y + z = 9
z = -3
The variables are:
x = -31
y = 12
z = -3

#### Work Step by Step

The matrix is represented by the following system of equations:
x + 2y - 2z = -1
y + z = 9
z = -3
Using back substitution to solve the system:
y - 3 = 9
y = 12
x + 2(12) - 2(-3) = -1
x + 24 + 6 = -1
x + 30 = -1
x = -31
The variables are:
x = -31
y = 12
z = -3