Results 1 to 6 of 6

Math Help - Simplify the complex fraction

  1. #1
    Newbie
    Joined
    Apr 2008
    Posts
    16

    Simplify the complex fraction

    I can barely simplify regular fractions! My book's explanation of how to do this has me so terribly confused...

    \frac{\frac{b}{b+9}+\frac{7}{5b}}{\frac{b}{3b+27}+  \frac{4}{b}}

    Thanks for any help you can offer.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,966
    Thanks
    1785
    Awards
    1
    Note that 3b+27=3(b+9).
    So the LCD is 15b(b+9).
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Apr 2008
    Posts
    16
    Quote Originally Posted by Plato View Post
    Note that 3b+27=3(b+9).
    So the LCD is 15b(b+9).
    So, I would simply each individual fraction, then multiply both numerators by the LCD right?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,966
    Thanks
    1785
    Awards
    1
    Quote Originally Posted by Fails_at_Math View Post
    So, I would simply each individual fraction, then multiply both numerators by the LCD right?
    Right.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor
    Joined
    Mar 2007
    Posts
    1,240

    Talking

    Quote Originally Posted by Fails_at_Math View Post
    \frac{\frac{b}{b+9}+\frac{7}{5b}}{\frac{b}{3b+27}+  \frac{4}{b}}
    Expanding a bit on the previous (and spot-on!) reply, multiply the fraction, top and bottom, by the LCM of the four sub-fractions:

     \frac{\displaystyle\frac{15b(b\, +\, 9)}{1}\left(\frac{b}{b\, +\, 9}\right)\, +\, \frac{15b(b\, +\, 9)}{1}\left(\frac{7}{5b}\right)}{\displaystyle\fra  c{15b(b\, +\, 9)}{1}\left(\frac{b}{3(b\, +\, 9)}\right)\, +\, \frac{15b(b\, +\, 9)}{1}\left(\frac{4}{b}\right)}

    Cancel stuff to get:

    \frac{15b(b)\, +\, 3(b\, +\, 9)(7)}{5b(b)\, +\, 15(b\, +\, 9)(4)}

    I'll bet you can see where to go from there!
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Apr 2008
    Posts
    16
    Now that I've finished my lunch...

    \frac{3(5b^2\, +\, 7b\, +\, 63)}{5(b^2\, +\, 12b\, +\, 108)}

    Should I leave it like this? Based on the answers of similar problems in the book, I think I should distribute it out to...

    \frac{15b^2\, +\, 21b\, +\, 189)}{5b^2\, +\, 60b\, +\, 540)}


    How's this look?

    Much appreciate the help guys.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Simplify Complex Fraction
    Posted in the Algebra Forum
    Replies: 2
    Last Post: August 12th 2011, 01:36 PM
  2. simplify complex fraction
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: September 13th 2010, 08:03 AM
  3. Simplify this complex fraction?
    Posted in the Algebra Forum
    Replies: 2
    Last Post: March 30th 2010, 09:40 PM
  4. Simplify the complex fraction
    Posted in the Algebra Forum
    Replies: 1
    Last Post: March 6th 2009, 07:41 PM
  5. simplify a complex fraction
    Posted in the Algebra Forum
    Replies: 2
    Last Post: June 10th 2008, 04:55 AM

Search Tags


/mathhelpforum @mathhelpforum