SOLUTION: solve each system of equations by the substitution method -3x+y=7 5x+2y=3

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Question 801691: solve each system of equations by the substitution method
-3x+y=7 5x+2y=3
Answer by waynest(281) About Me  (Show Source):
You can put this solution on YOUR website!
-3x + y = 7
-3x + 3x + y = 3x + 7
y = 3x + 7
substitute this for y in the second equation
5x + 2(3x + 7) = 3
5x + 6x + 14 = 3
11x + 14 - 14 = 3 - 14
11x = -11
11x/11 = -11/11
x = -1
substitute x into the equation
-3(-1) + y = 7
3 + y = 7
3 - 3 + y = 7 - 3
y = 4
check:
-3(-1) + 4 = 7
3 + 4 = 7
7 = 7
5(-1) + 2(4) = 3
-5 + 8 = 3
3 = 3