Answer:
A. x = 3; y = 5; z = 9
Explanation:
7 4 -1 32
4 1 -3 -10
1 2 1 22
Switch rows 1 and 3.
1 2 1 22
4 1 -3 -10
7 4 -1 32
R2 --> -4 × R1 + R2
1 2 1 22
0 -7 -7 -98
7 4 -1 32
R3 --> -7 × R1 + R3
1 2 1 22
0 -7 -7 -98
0 -10 -8 -122
R2 --> -1/7 × R2
1 2 1 22
0 1 1 14
0 -10 -8 -122
R1 --> -2 × R2 + R1
1 0 -1 -6
0 1 1 14
0 -10 -8 -122
R3 --> 10 × R2 + R3
1 0 -1 -6
0 1 1 14
0 0 2 18
R3 --> 1/2 × R2
1 0 -1 -6
0 1 1 14
0 0 1 9
R2 --> -R3 + R2
1 0 -1 -6
0 1 0 5
0 0 1 9
R1 --> R1 + R3
1 0 0 3
0 1 0 5
0 0 1 9
Answer: A. x = 3; y = 5; z = 9