Diketahui 3 persamaan 2x+3y-2z=3 4x+y+5z=0 x+4y+2z=12 Tentukan nilai x,y dan z yang memenuhi persamaan tersebut

misal : 4x + y + 5z = 0
y = -4x - 5z
2x + 3y - 2z = 3
2x + 3(-4x - 5z) - 2z = 3
2x - 12x - 15z - 2z = 3
-10x - 17z = 3 ... pers 1

x + 4y + 2z = 12
x + 4(-4x - 5z) + 2z = 12
x - 16x - 20z + 2z = 12
-15x - 18z = 12 ... pers 2

pers 1 & 2
-10x - 17z = 3 |X3|
-15x - 18z = 12. |X2|
-30x - 51z = 9
-30x - 36z = 24
------------------------ (-)
- 15z = - 15
z = 1

-10x - 17z = 3
-10x - 17(1) = 3
-10x - 17 = 3
-10x = 3 + 17
-10x = 20
x = -2

y = -4x - 5z
y = -4(-2) - 5(1)
y = 8 - 5 = 3