SOLUTION: Need help solving systems in three variable - x+y+z=57,-2x+y+=3,x-z=6

Algebra ->  Graphs -> SOLUTION: Need help solving systems in three variable - x+y+z=57,-2x+y+=3,x-z=6      Log On


   

Question 902201: Need help solving systems in three variable - x+y+z=57,-2x+y+=3,x-z=6
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
From eq. 3,
x-z=6
z=x-6
Substitute into eq. 1,
x%2By%2B%28x-6%29=57
2x%2By=63
Then from eq. 2,
y=3%2B2x
Substituting,
2x%2B%283%2B2x%29=63
4x=60
x=15
Now working backwards,
y=3%2B2%2815%29
y=3%2B30
y=33
and finally,
z=15-6
z=9