SOLUTION: I am having trouble with factoring by grouping.This is the problem: {{{ab+7b-3a-21}}}. Could you please help me out? Thanks.

Algebra ->  Expressions -> SOLUTION: I am having trouble with factoring by grouping.This is the problem: {{{ab+7b-3a-21}}}. Could you please help me out? Thanks.      Log On


   

Question 8430: I am having trouble with factoring by grouping.This is the problem: ab%2B7b-3a-21. Could you please help me out? Thanks.
Answer by drglass(89) About Me  (Show Source):
You can put this solution on YOUR website!
Start by separating the equation into two groups. Let's start with ab and 7b. Factor b from these terms to get b%28a+%2B+7%29+-+3a+-+21. Next factor -3 from -3a and -21 to get b%28a+%2B+7%29+-+3%28a+%2B+7%29. Finally, factor %28a+%2B+7%29 to get %28a+%2B+7%29%28b+-+3%29