hitunglah nilai x-y-z dari persamaan linier berikut.: x+y+z=12 2x-y+2z=12 2x+2y-z =18

pers1=x+y+z=12
pers2=2x-y+2z=12
pers3=2x+2y-z=18
x+y+z =12
2x-y +2z=12
--------------- +
3x+3z=24 pers4
sub.pers 1&4
x+y+z. =12
3x- y+2z=24
--------------- +
4x+3z=36 pers5
pers4&5
3x+3z=24
4x+3z=36
------------- --
-x=-12
x=12
subx=12 ke pers4
3x+3z. =24
3(12)+3z=24
36+3z=24
3z=24-36
3z=-12
Z=-4
sub x,z ke pers 1
x+y+z=12
12+y+(-4)=12
12+y-4=12
y=12-12+4
y=4
maka nilai
x=12,y=4,z=-4