Solve this problem

Question

Answer 1

2x - 2y = 4 (1)

3x + z = 9 (2)

3y + 3z = -3 (3)

Solve (1) for x

2x - 2y = 4

x = (2y + 4)/2

x = y + 2

Substitute x in equation (2)

3(y+2) -z = 9

3y + 6 -z = 9

3y + z = 9 - 6

3y + z = 3 (4)

Now solve (4) and (3)

3y + z = 3 (4) multiply by -1

3y + 3z = -3 (3)

-3y - z = -3

3y + 3z = -3

2z = -6 z = -3

Substitute z in (3)

3y + 3(-3) = -3

3y - 9 = -3

3y = -3 + 9

3y = 6 y = 2

Substitute y in (1)

2x - 2(2) = 4

2x - 4 = 4

2x = 4 + 4

2x = 8 x = 4