Tentukan hp dari X+y+z=2 2x-y+z=-1 X-4y-z=0 Dengan cara metode eliminasi dan subtitusi

Eliminasi pers (1) dan (2)
x+y+z =2[2] 2x+2y+2z=2
2x-y+z=-1[1] 2x-y+z =-1
__________-
3y+z =3
Eliminasi pers (2) dan (3)
2x-y+z=-1[1] 2x-y+z =-1
x-4y-z=0[2] 2x-8y-2z=0
__________-
7y+3z=-1
Eliminasi pers (4) dan (5)
3y+z =3[7] 21y+7z=21
7y+3z=-1[3] 21y+9z=-3
_________-
-2z=24
z=-12
Substitusikan
3y+z =3
3y+(-12)=3
3y =3+12
3y =15
y =5
Substitusikan
x+y+z =2
x+(5)+(-12)=2
x+(-7) =2
x =2+7
x =9
Jadi nilai
x=9
y=5
z=-12