Question 214891This question is from textbook Elementary & intermediate algebra
: How to solve a+b+c=5 2a+3b-c=2 2a+3b-2c=4
This question is from textbook Elementary & intermediate algebra
Answer by RAY100(1637)   (Show Source):
You can put this solution on YOUR website! (1) a+b+c = 5
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(2) 2a +3b -c =2
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(3) 2a +3b -2c = 4
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(3) - (2)
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(-2c)-(c) = 4-2 = 2
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-c =2
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c=(-2),,,,,,subst in (1),,,,,
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a+b-2 =5
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a+b = 7
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Mult by 2
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2a+2b = 14
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Subst in (2),,,2a +3b -c = 2
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2a +3b +2 =2,,,,2a +3b =0
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Subtract ,,{2a +2b =14 }-{2a +3b =0},,,
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-b=14,,,,b=(-14)
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Subst in (1),,,a+b+c= 5,,,,a-14-2=5,,,,,a=21
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check (1) 21 -14 -2 =5,,,,ok
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(2) 2(21) +3(-14) -(-2) = 2,,,,42 -42 +2=2,,,,ok
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(3) 2(21) +3(-14) -2(-2) =4,,,,42 -42 +4=4,,,,ok
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