Solving Systems of equations with row operations

Question

2x - y - 5z = 11

x + 3y + 2z = 14

3x + 8y + 7z = 35

Answer 1

2 -1 -5 11

1 3 2 14

3 8 7 35

-2*row2+ row1; -3*row2+row3

0 -7 -9 -17

1 3 2 14

0 -1 1 -7

-7*row3 + row1

0 0 -16 32

1 3 2 14

0 -1 1 -7

z=-2

-y + z = -7

-y + -2 = -7

-y = -5

y=5

x + 3(5) + 2(-2) = 14

x + 15 + -4 = 14

x + 11 = 14

x = 3

{3,5,-2}