SOLUTION: how do I solve this system by using the substitution method? x + 3y = -1 y = -2x-12

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Question 929966: how do I solve this system by using the substitution method?
x + 3y = -1
y = -2x-12

Answer by TimothyLamb(4379) About Me  (Show Source):
You can put this solution on YOUR website!
x + 3y = -1
y = -2x-12
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put the system of linear equations into standard form
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x + 3y = -1
-2x - y = 12
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copy and paste the above standard form linear equations in to this solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
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solution:
x = -7
y = 2
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by substitution:
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x + 3y = -1
y = -2x - 12
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x + 3(-2x - 12) = -1
x - 6x - 36 = -1
-5x = 35
x = -7
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y = -2x - 12
y = -2*(-7) - 12
y = 2
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solution by substitution:
x = -7
y = 2
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