Results 1 to 4 of 4

Math Help - adding and subtracting rational expressions

  1. #1
    Senior Member euclid2's Avatar
    Joined
    May 2008
    From
    Ottawa, Canada
    Posts
    400
    Awards
    1

    adding and subtracting rational expressions

    a)4x+1/3x-5 + 2x/12x-20

    b) 3x-1/x^2+4x+3 - x+6/2x^2+7x+1

    Simplify and state restrictions on the variable
    Please help
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member Glaysher's Avatar
    Joined
    Aug 2006
    From
    Newton-le-Willows
    Posts
    224
    Quote Originally Posted by euclid2 View Post
    a)4x+1/3x-5 + 2x/12x-20

    b) 3x-1/x^2+4x+3 - x+6/2x^2+7x+1

    Simplify and state restrictions on the variable
    Please help
    (a) First factorise and cancel where possible

    4x+1/3x-5 + 2x/12x-20 = 4x+1/3x-5 + 2x/4(3x-5) = 4x+1/3x-5 + x/2(3x-5)

    Then multiply the top and bottom of each fraction so that they have the same denominator

    = 2(4x+1)/2(3x-5) + 2x/4(3x-5)

    Then add the fractions together

    = (8x+2+2x)/2(3x-5) = (10x+2)/2(3x-5)

    Finally factorise and cancel down if possible

    = 2(5x+1)/2(3x-5) = (5x+1)/(3x-5)

    (b) similar
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member euclid2's Avatar
    Joined
    May 2008
    From
    Ottawa, Canada
    Posts
    400
    Awards
    1
    what would be the restrictions or how do you get the restrictions?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Apr 2005
    Posts
    16,416
    Thanks
    1853
    Quote Originally Posted by euclid2 View Post
    what would be the restrictions or how do you get the restrictions?
    The denominators in the individual fractions cannot be 0. Set each denominator equal to 0 and solve for x to see values of x that CANNOT be allowed.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 12
    Last Post: July 19th 2009, 09:55 PM
  2. Adding and Subtracting Rational Expressions
    Posted in the Algebra Forum
    Replies: 4
    Last Post: April 8th 2009, 06:12 AM
  3. adding and subtracting rational expressions
    Posted in the Algebra Forum
    Replies: 1
    Last Post: November 9th 2008, 05:52 PM
  4. Adding/ Subtracting rational expressions
    Posted in the Algebra Forum
    Replies: 3
    Last Post: October 3rd 2007, 04:12 PM
  5. Adding and Subtracting Rational Expressions
    Posted in the Algebra Forum
    Replies: 7
    Last Post: May 14th 2007, 10:06 PM

Search Tags


/mathhelpforum @mathhelpforum