SOLUTION: -7x+y=20 9x-3y=36

Algebra ->  Algebra  -> Linear-equations -> SOLUTION: -7x+y=20 9x-3y=36      Log On

Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!
Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!

   

Question 148590: -7x+y=20
9x-3y=36
Answer by Fombitz(13828) About Me  (Show Source):
You can put this solution on YOUR website!
1.-7x%2By=20
2.9x-3y=36
Use eq. 1 to solve for y in terms of x.
1.-7x%2By=20
y=20%2B7x
Now substitute this expression into eq. 2 and solve for x.
2.9x-3y=36
9x-3%2820%2B7x%29=36
9x-60-21x=36
-12x=96
x=-8
Now back substitute to find y.
y=20%2B7x
y=20%2B7%28-8%29
y=20-56
y=-36