SOLUTION: What is the process for solving systems of equations by substitution? Example: -5x + y = -2 and -3x + 6y = _12 I know that you need to isolate the y in the first problem by add

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Question 679262: What is the process for solving systems of equations by substitution?
Example: -5x + y = -2 and -3x + 6y = _12
I know that you need to isolate the y in the first problem by adding 5x to both sides. That gives you y = -2 + 5x, which you next plug in to the other equation to get -3x + 5x + -2 +6y = -12. Right? This math book only has instructions for simpler problems. I don't know what to do next.
Thanks. Any help would be welcome.
Found 2 solutions by ReadingBoosters, checkley79:
Answer by ReadingBoosters(3246) About Me  (Show Source):
You can put this solution on YOUR website!
-5x + y = -2
-3x +6y = -12
...
y = -2 + 5x
Substitute into the second equation for the "y"
...
-3x + 6(-2+5x) = -12
Distribute the 6
-3x - 12 + 30x = -12
27x - 12 = -12
27x = 0
x = 0
...
Plug the x into either equation and solve for y
y = -2 + 5(0) = -2
...
x = 0
y = -2
...
Check
-5(0) + -2 = -2 : Correct
-3(0) + 6(-2) = -12 : Correct
.....................
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Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
-5x + y = -2
y=5x-2
-3x + 6y = _12
-3x+6(5x+2)=12
-3x+30x+12=12
27x=12-12
27x=0
x=0/27=0 ans.
y=5*0-2
y=0+2=2 ans.
Proof:
-3*0+6*2=12
0+12=12
12=12