SOLUTION: solve by elimination a+b+c=-3 3b-c=4 2a-b-2c=-5

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Question 371030: solve by elimination
a+b+c=-3
3b-c=4
2a-b-2c=-5
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
1.a%2Bb%2Bc=-3
2.3b-c=4
3.2a-b-2c=-5
Multiply eq. 1 by (-2) and add to eq. 3,
-2a-2b-2c%2B2a-b-2c=6-5
4.-3b-4c=1
Add eq. 2 to eq. 4,
3b-c-3b-4c=4%2B1
-5c=5
highlight%28c=-1%29
Then from eq. 2,
3b%2B1=4
3b=3
highlight%28b=1%29
From eq. 1,
a%2B1-1=-3
highlight%28a=-3%29