SOLUTION: Which process would you use to solve both of the following systems of equations, the addition method or the substitution method? Are they both applicable to use, or would one metho

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Question 141596: Which process would you use to solve both of the following systems of equations, the addition method or the substitution method? Are they both applicable to use, or would one method be easier to use than the other? Please EXPLAIN your responses.
System 1:
x + y = 7
x - y = 9
System 2:
3x - 4y = 11
-2x + 3y = -7
Answer by Fombitz(32388) (Show Source):
You can put this solution on YOUR website!
Both systems are always available for you to use.
They will give you the same results.
Sometimes one method is faster than another.
For system 1, addition is fastest because you have positive y in one equation and negative y in the other.
Adding them together cancels y's out.

Add the two together to get.

For system 2, addition is also faster, but requires some multiplication first.
In this case, substitution would give you nasty fractions and more multiplication.
It's not impossible, but it can become cumbersome and easy to make a mistake.

Multiply the first by 3, the second by 4, then add.