pleasee bantu aku, sebisa kalian aja no brp, bsk aku ulangan T_T

1. ( x+y+z=-6) - (x-2y+z=3)=
3y = -9
y=-9/3
y= -3

x=-6-y-z
= -6+3-z
= -3-z

z= -6-x-y
= -6-(-3-z)+3
= 0

x = -6-y-z
= -3-0
= -3