This is the elimination method (don't know if that's what your teacher means by the linear combination method. I think this is ok because you are just taking a linear combination of Equations A and B to yield another equation).
Add the two equations A and B to ge 9x=-9 or x=-1. Substituting x=-1 into Equation A yields -4+2y=2 or 2y=6 and y=3.
So solution is (-1,3).
The following solves using the Substituion method with the same results.
Solve: We'll use substitution. After moving 2*y to the right, we get: , or . Substitute that
into another equation: and simplify: So, we know that y=3. Since , x=-1.
Answer: .
I hope the above steps were helpful.
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And good luck in your studies!
Respectfully,
Dr J
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