SOLUTION: solve 2x-y=21 x=4y

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Question 1106170: solve
2x-y=21
x=4y
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
solve
2x-y=21
x=4y
===============
You should say "solve for x & y"
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Sub for x in the 1st equation.
2x-y=21
2*4y - y = 21
8y - y = 21
7y = 21
y = 3
============
x = 4y
x = 12