SOLUTION: I do not know how to solve this. Solve by substitution x+y=10 y=4x

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Question 177559: I do not know how to solve this.
Solve by substitution
x+y=10
y=4x
Answer by Mathtut(3670) About Me  (Show Source):
You can put this solution on YOUR website!
x+y=10......eq 1
y=4x........eq 2
:
take y's value of 4x from eq 2 and plug it into eq 1.
:
x+(4x)=10
:
5x=10
:
highlight%28x=2%29
:
now take x's found value and plug it back into either eq 1 or 2. I choose eq 2
:
highlight%28y=4%282%29=8%29