SOLUTION: Solve the system of equations by substitution. 3x + y = 13 2x - 7y = 24

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Question 420142: Solve the system of equations by substitution.
3x + y = 13
2x - 7y = 24
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
From the top equation, y = 13 - 3x. Then
2x - 7(13 - 3x) = 24
==> 2x - 91 + 21x = 24
==> 23x = 115
==> x = 5.
==> y = 13 - 3*5 = 13 - 15 = -2.