SOLUTION: referring to questions 163893,159668,159276.I understand grouping like expressions,such as a's go together b's go together c's go together and so on.But when I've tried to work pro

Algebra ->  Algebra  -> Expressions -> SOLUTION: referring to questions 163893,159668,159276.I understand grouping like expressions,such as a's go together b's go together c's go together and so on.But when I've tried to work pro      Log On

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Question 164278: referring to questions 163893,159668,159276.I understand grouping like expressions,such as a's go together b's go together c's go together and so on.But when I've tried to work problems I can't tell when I should add and when I should subtract.For example 3a-5-2b+3a+7b-2.My answer was 6a-2-9b.The correct answer was 6a+5b-7.
Answer by Fombitz(13823) About Me  (Show Source):
You can put this solution on YOUR website!
How's this... change all of the operations to addition.
Negative numbers get parentheses around them.
Then sort and combine.
Maybe that'll work better.
3a-5-2b%2B3a%2B7b-2=3a%2B%28-5%29%2B%28-2b%29%2B3a%2B7b%2B%28-2%29
3a-5-2b%2B3a%2B7b-2=3a%2B3a%2B%28-2b%29%2B7b%2B%28-5%29%2B%28-2%29
3a-5-2b%2B3a%2B7b-2=a%283%2B3%29%2Bb%287-2%29%2B%28-5-2%29
3a-5-2b%2B3a%2B7b-2=6a%2B5b%2B%28-7%29
3a-5-2b%2B3a%2B7b-2=6a%2B5b-7