SOLUTION: 2x-y -1 7x+6y=-6

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Question 1098542: 2x-y -1
7x+6y=-6


Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39618) About Me  (Show Source):
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!

While the solution by the other tutor is fine, I don't understand why so many people use substitution to solve pairs of equations that are given in this form, when elimination seems to me so much easier.

2x-y+=1
7x%2B6y=-6

multiply the first equation by 6 so that the y term is "-6y"; then when you add the two equations the y is eliminated, giving you a simple equation to solve for x:
12x-6y+=+6
7x%2B6y+=+-6
19x+=+0 [adding the two equations]
So x = 0; now substitute that value in either of the original equations.
2%280%29-y+=+1
-y+=+1
and so y = -1.

The solution is (x,y) = (0,-1).