SOLUTION: Solve the following by back substitution: x-3y+2z-w=-7 y-z+w=0 3z-3w=3 2w=-8

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Question 818581: Solve the following by back substitution:
x-3y+2z-w=-7
y-z+w=0
3z-3w=3
2w=-8
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
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