I keep getting the wrong answer

Question

perform the specific elementary row operation and type the resulting system of equations.

the first one is (Eq1) => (Eq3)

-x + y - z = 10

3x - 2y + 6z = 4

x + 2y+ z =5

it's the same equation but with (Eq1) + (Eq3) => (Eq3)

Answer 1

Not sure about your first row operation notation. I guess (Eq1) => (Eq3) means swap row 1 and 3?

If not, then the following operations will not be correct.

-1 1 -1 10

3 -2 6 4

1 2 1 5

Swap r1 and r3

1 2 1 5

3 -2 6 4

-1 1 -1 10

r3 = r1 + r3

1 2 1 5

3 -2 6 4

0 3 0 15