SOLUTION: substitution 4x+y=15 -x-3y=-12

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Question 365193: substitution
4x+y=15
-x-3y=-12
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
The bottom equation gives 12-3y = x. substitute this into the top equation:
4(12-3y)+y = 15,
48-12y + y = 15,
48-11y = 15,
-11y = 15-48,
-11y = -33,
y = 3, and x = 12-3*3 = 12-9 = 3.