There are several ways you can solve this problem if you're trying to solve for m and n. You can substitute, or systems of equations. However, I'm going to use substitution:
2m + n = 0 => n = -2m
We can input that in for the other equation:
m + 2n = 3 now becomes: m + 2(-2m) = 3
Now we can solve:
m + 2(−2m) = 3
m + −4m = 3
(m + −4m) = 3 (Combine Like Terms)
−3m=3
m = -1
Now we can input that value in to solve for n:
We said that n = -2m, and m = -1, so n = -2(-1):Answer:
n = 2
Your final answer is m = -1, and n = 2, which can also be written as (m,n) = (-1,2)
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However, if you were solving for m+n:
You would add the two equations!:
2m + n = 0
m + 2n = 3
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3m + 3n = 3
Now, you can take 3 common:
3(m+n) = 3
m + n = 1
Your final answer for what m + n equals 1!
