Results 1 to 4 of 4

Math Help - Common Factors

  1. #1
    Junior Member
    Joined
    May 2010
    Posts
    26
    Thanks
    1

    Common Factors

    Factor by grouping

    xy + 12 + 4x + 3y = (x+3)(4+y)<-------txtbk ans

    x + x - xy - y = (x+1)(x-y)<--------txtbk ans


    Please help. I'm confused how to arrive to the answer. Can someone show me the steps? Thank you!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    xy + 12 + 4x + 3y

    xy + 3y + 4x+ 12

    y(x + 3) + 4(x+ 3)

    (x + 3)(y+4)

    Do you follow?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    May 2010
    Posts
    26
    Thanks
    1
    Quote Originally Posted by pickslides View Post
    xy + 12 + 4x + 3y

    xy + 3y + 4x+ 12

    y(x + 3) + 4(x+ 3)

    (x + 3)(y+4)

    Do you follow?
    Do you always have to rearrange the expression before solving?

    Can't it also say x(y+4)+3(4+y) in the 3rd step?

    And how would you know to group which ones together?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,236
    Thanks
    28
    Quote Originally Posted by larry21 View Post
    Do you always have to rearrange the expression before solving?
    Only so you can take out a common factor.


    Quote Originally Posted by larry21 View Post
    Can't it also say x(y+4)+3(4+y) in the 3rd step?
    Yep, addition commutes.

    Quote Originally Posted by larry21 View Post

    And how would you know to group which ones together?
    You try to find groups where there is a common factor that once taken out gives the same inside each bracket. Sometimes might take a little trial and error. Perseverance will be your friend.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Extraction and Grouping Common Factors help!
    Posted in the Algebra Forum
    Replies: 7
    Last Post: December 5th 2010, 07:03 AM
  2. What factors do 4,6,7 have in common
    Posted in the Algebra Forum
    Replies: 11
    Last Post: October 9th 2009, 05:02 AM
  3. Extraction and Grouping Common Factors help!
    Posted in the Algebra Forum
    Replies: 2
    Last Post: January 12th 2009, 04:57 AM
  4. Grouping Common Factors
    Posted in the Algebra Forum
    Replies: 3
    Last Post: March 15th 2008, 12:58 AM
  5. greatest common factors
    Posted in the Number Theory Forum
    Replies: 7
    Last Post: March 13th 2008, 11:54 PM

Search Tags


/mathhelpforum @mathhelpforum