SOLUTION: Solve this system of equations by the substitution method. x+4x=-1 3x+y=8

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Question 314760: Solve this system of equations by the substitution method.

x+4x=-1
3x+y=8
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
I think this is what you mean,
1.x%2B4y=-1
2.3x%2By=8
From eq. 1,
x=-4y-1
3x=-12y-3
Substitute into eq. 2,
%28-12y-3%29%2By=8
-11y=11
highlight%28+y=-1%29
Then from above,
x=-4y-1
x=-4%28-1%29-1
x=4-1
highlight%28+x=3%29