Tentukan himpunan penyelesaian dari persamaan x + y + z = -1 , x + 2y + 3z =5 ,dan 3x -2y-z=9

x + y + z = -1
x + 2y + 3z = 5
--------------- -
-y -2z = -6
-2z = -6 + y
z = 3 - y/2

x + y + z = -1
x + y + 3 -y/2 = -1
2x + 2y + 6 -y = -2
2x + y = -8
x + y/2 = -4
x = -4 - y/2

x + y + z = -1
-4 -y/2 + y + 3 -y/2 = -1
-8 -y + 2y + 6 -y = -2
0

hp{-4 -y/2, 0, 3 -y/2}