Question 818581
x-3y+2z-w=-7
y-z+w=0
3z-3w=3
2w=-8
.
2w=-8
w=-4
.
3z-3w=3
3z-(3*-4)=3
3z+12=3
3z=-9
z=-3
.
y-z+w=0
y-(-3)+(-4)=0
y+3-4=0
y=1
.
x-3y+2z-w=-7
x-3+2(-3)+(-4)=-7
x-3-6-4=-7
x=6
.
Ed