hasil dari x-2y+z=7 2×+3y-z=7 x+y=4

x-2y+z=7
2x+3y-z= 7
----------------+
3x+y= 14

3x+y= 14
x+y= 4
------------- -
2x= 10
x= 5

x+y= 4
5+y= 4
y= 4-5
y= -1

x-2y+z= 7
5-2.-1+z= 7
5+2+z= 7
7+z= 7
z= 0

jadi, x = 5, y = -1 ,dan z = 0. semoga membantu♥