{2x+y-z=1,x-y+z=5,3x+2y+2z=24}adalah...

2x + y - z = 1 ........ (1)
x - y + z = 5............(2)
3x + 2y + 2z= 24..(3)

pers (1) dan (2)
2x + y - z = 1 | 1 | 2x + y - z = 1
x - y + z= 5 | 2 | 2x - 2y+2z= 10
_____________-
3y - 3z = -9 ....(4)

pers (2) dan (3)
x - y + z = 5 | 3 | 3x - 3y + 3z = 15
3x+2y+2z=24 | 1 | 3x+ 2y + 2z = 24
______________-
-5y - z = -9
5y + z = 9.....(5)

pers (4) dan (5)
3y - 3z = -9 | 5 | 15y - 15z = -45
5y + z = 9 | 3| 15y+ 3z = 27
____________-
-18z = -72
z = -72/-18 = 4

5y + z = 9
5y + 4 = 9
5y = 9 - 4
5y = 5
y = 5/5 =1

x - y + z = 5
x - 1 + 4 = 5
x + 3 = 5
x = 5 - 3
= 2