SOLUTION: Solve the system of equation by the method of substitution. y=7x 4x - y = -12

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Question 995752: Solve the system of equation by the method of substitution.
y=7x
4x - y = -12
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

+y=7x.......eq.1
4x+-+y+=+-12.......eq.2
----------------------------------substitute 7x for y in eq.2
4x+-+7x+=+-12.......eq.2....solve for x
-+3x+=+-12......both sides multiply by -1
%28-1%29%28-+3x%29+=+%28-1%29%28-12%29
3x+=+12
x+=+12%2F3
highlight%28x+=+4%29
go back to eq.1,substitute 4 for x
+y=7%2A4.......eq.1
+highlight%28y=28%29
solution to this system:
highlight%28x+=+4%29 and +highlight%28y=28%29
it means given lines intersect at point (4,28)