{-x – y – z = -8 (1)
{-4 + 4y + 5z = 7 (2)
{2x + 2z = 4 (3)
divide equation (3) by 2
x + z = 2 so z = 2 -x
substitute z = 2 -x into (1)
-x – y – z = -8
-x - y - (2 -x) = -8
-x - y -2 + x = -8
-y = -6
y = 6
-4 + 4y + 5(2 -x) = 7
-4 + 4y + 10 - 5x = 7
6 + 4y - 5x = 7
4y - 5x = 1
4(6) - 5x = 1
5x = 23
x = 4.6
z = 2 - x
z = 2 - 4.6
z = -2.6
answer
x = 4.6, y = 6 and z = -2.6
