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!
30%*470=141 (So the number of students in 8 grade is 141)
Your answer would be (3,0)
ANSWER

EXPLANATION
It was given that, Joan has

and she will use

of it to make place cards.
We want to find how felt she will use for place cards.
We just have to find,



Therefore Joan will use

yards of felt for the place cards.