SOLUTION: solve each system of equatioins by using substitution m+n=20 m-n=-4 work: m+n=20 -n -n ---------- 20-n m-n=-4 20-n-n=-4 (20-n)=-4 -4

Algebra ->  Algebra  -> Systems-of-equations -> SOLUTION: solve each system of equatioins by using substitution m+n=20 m-n=-4 work: m+n=20 -n -n ---------- 20-n m-n=-4 20-n-n=-4 (20-n)=-4 -4      Log On

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Question 239833: solve each system of equatioins by using substitution
m+n=20
m-n=-4
work: m+n=20
-n -n
----------
20-n
m-n=-4
20-n-n=-4
(20-n)=-4
-4n-80
~ thats all i could come up with....
Answer by checkley77(12569) About Me  (Show Source):
You can put this solution on YOUR website!
m+n=20
m=20-n
Now replace m in the following equation with 20-n
m-n=-4
(20-n)-n=-4
-2n=-4-20
-2n=-24
n=-24/-2
n=12 ans.
m+12=20
m=20-12
m=8 ans.