tolong bantu yaa sama penjelasannya juga

x+3y-z=13|×3
3x+y-z=11|×1
jadi:
3x+9y-3z=39
3x+y-z=11
_____________-
8y-2z=28

x+3y-z=13
x+y-3z=11
_________-
2y+2z=2


8y-2z=28|×1
2y+2z=2|×4
jadi:
8y-2z=28
8y+8z=8
_________-
-10z=20
z=20/-10
z=-2

8y-2z=28
2y+2z=2
_________+
6y=30
y=30/6
y=5

x+3y-z=13
x+3(5)-(-2)=13
x+15+2=13
x+17=13
x=13-17
x=-4
HP={-4,5,-2}
nilai dari
2x+2y-6z
2(-4)+2(5)-6(-2)
-8+10+12
=14