document.write( "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. \n" ); document.write( "
Algebra.Com's Answer #121039 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
How's this... change all of the operations to addition.
\n" ); document.write( "Negative numbers get parentheses around them.
\n" ); document.write( "Then sort and combine.
\n" ); document.write( "Maybe that'll work better.
\n" ); document.write( "\"3a-5-2b%2B3a%2B7b-2=3a%2B%28-5%29%2B%28-2b%29%2B3a%2B7b%2B%28-2%29\"
\n" ); document.write( "\"3a-5-2b%2B3a%2B7b-2=3a%2B3a%2B%28-2b%29%2B7b%2B%28-5%29%2B%28-2%29\"
\n" ); document.write( "\"3a-5-2b%2B3a%2B7b-2=a%283%2B3%29%2Bb%287-2%29%2B%28-5-2%29\"
\n" ); document.write( "\"3a-5-2b%2B3a%2B7b-2=6a%2B5b%2B%28-7%29\"
\n" ); document.write( "\"3a-5-2b%2B3a%2B7b-2=6a%2B5b-7\"
\n" ); document.write( "
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