#### Answer

The solution set is (4,8,5,2).

#### Work Step by Step

Starting from the original matrix:
1 -1 0 0 -4
0 1 -3 0 -7
0 0 1 -3 -1
0 0 0 2 4
We do the following operations:
Divide the last row by 2
1 -1 0 0 -4
0 1 -3 0 -7
0 0 1 -3 -1
0 0 0 1 2
add 3 times the 4th row to the 3rd row
1 -1 0 0 -4
0 1 -3 0 -7
0 0 1 0 5
0 0 0 1 2
add 3 times the 3rd row to the 2nd row
1 -1 0 0 -4
0 1 0 0 8
0 0 1 0 5
0 0 0 1 2
add the 2nd row to the 1st row
1 0 0 0 4
0 1 0 0 8
0 0 1 0 5
0 0 0 1 2
And the solution set is the last entries of each row, in order.