Results 1 to 12 of 12

Math Help - rational expressions

  1. #1
    Junior Member Cait's Avatar
    Joined
    Mar 2007
    From
    MI, unfortunately
    Posts
    32

    rational expressions

    ok ive got like 50 questions here @_@ but im guna post one to start out to see if maybe that mistake will fix the rest as well..

    http://aycu22.webshots.com/image/113...3916155_rs.jpg

    Tell me what im doing wrong?

    Thanks so much
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Junior Member Cait's Avatar
    Joined
    Mar 2007
    From
    MI, unfortunately
    Posts
    32

    Thumbs down

    bumper?

    another problem is...

    5/x-2 + 6

    book's answer is 6x-7/x-2

    ....
    and i got

    6x+3/x-2
    Follow Math Help Forum on Facebook and Google+

  3. #3
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by Cait View Post
    ok ive got like 50 questions here @_@ but im guna post one to start out to see if maybe that mistake will fix the rest as well..

    http://aycu22.webshots.com/image/113...3916155_rs.jpg

    Tell me what im doing wrong?

    Thanks so much
    you are incorrect, you forgot to keep the x - 2 in brackets

    5/(x-2) + 6
    = 5/(x - 2) + 6*(x - 2)/(x - 2) ...................here you put 6x - 2, that's wrong, it's 6(x - 2)
    = 5/(x - 2) + (6x - 12)/(x - 2)
    = (6x - 7)/(x - 2)
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,927
    Thanks
    332
    Awards
    1
    Quote Originally Posted by Cait View Post
    ok ive got like 50 questions here @_@ but im guna post one to start out to see if maybe that mistake will fix the rest as well..

    http://aycu22.webshots.com/image/113...3916155_rs.jpg

    Tell me what im doing wrong?

    Thanks so much
    For the first one:
    x/(x^2 - 1) - 7/(1 - x^2)

    = x/(x^2 - 1) + 7/(x^2 - 1)

    = (x + 7)/(x^2 - 1)

    The second one:
    5/(x - 2) + 6

    = 5/(x - 2) + 6(x - 2)/(x - 2)

    = 5/(x - 2) + (6x - 12)/(x - 2)

    = (5 + 6x - 12)/(x - 2)

    = (6x - 7)/(x - 2)

    -Dan
    Follow Math Help Forum on Facebook and Google+

  5. #5
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by Cait View Post
    ok ive got like 50 questions here @_@ but im guna post one to start out to see if maybe that mistake will fix the rest as well..

    http://aycu22.webshots.com/image/113...3916155_rs.jpg

    Tell me what im doing wrong?

    Thanks so much
    here:
    Attached Thumbnails Attached Thumbnails rational expressions-rat.gif  
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    9,927
    Thanks
    332
    Awards
    1
    Quote Originally Posted by Jhevon View Post
    here:
    Factoring a simple -1 from the second denominator does wonders, doesn't it?

    -Dan
    Follow Math Help Forum on Facebook and Google+

  7. #7
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by topsquark View Post
    Factoring a simple -1 from the second denominator does wonders, doesn't it?

    -Dan
    that it does. i waited until i combined fractions before i took out the -1 however, but we could have done it as easy in the beginning
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Junior Member Cait's Avatar
    Joined
    Mar 2007
    From
    MI, unfortunately
    Posts
    32

    Unhappy

    Omg i am retarded...

    with that picture i posted the problem to #21.. and the work to #25.



    Ugh this still doesnt explain..


    #21 is..

    x/x^2-1 - 7/1-x^2

    and THEIR answer is 1/x-2.

    and /I/ and YOU guys got x+7/x^2-1



    Is the book wrong????????
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Junior Member Cait's Avatar
    Joined
    Mar 2007
    From
    MI, unfortunately
    Posts
    32
    ok here's another..

    5x/x+2 - 3x-4/x+2


    The books answer is 2. Just plain 2.


    MY answer i get is 2x+4/x+2.



    So what'd i do wrong here??

    or is the answers in this book just sucking today? lol
    Follow Math Help Forum on Facebook and Google+

  10. #10
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by Cait View Post
    Omg i am retarded...

    with that picture i posted the problem to #21.. and the work to #25.



    Ugh this still doesnt explain..


    #21 is..

    x/x^2-1 - 7/1-x^2

    and THEIR answer is 1/x-2.

    and /I/ and YOU guys got x+7/x^2-1



    Is the book wrong????????
    yes, the book is wrong. or maybe you looked up the answer to a different prob by accident.

    you can see that the answer is wrong for yourself.

    plug in for instance, x = 3 into x/x^2-1 - 7/1-x^2, you get a different answer from when you plug in x = 3 into 1/(x - 2)
    Follow Math Help Forum on Facebook and Google+

  11. #11
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by Cait View Post
    ok here's another..

    5x/x+2 - 3x-4/x+2


    The books answer is 2. Just plain 2.


    MY answer i get is 2x+4/x+2.



    So what'd i do wrong here??

    or is the answers in this book just sucking today? lol
    you are correct, but you should simplify. your answer is 2 as well

    (2x + 4)/(x + 2) = 2(x + 2)/(x + 2) = 2
    Follow Math Help Forum on Facebook and Google+

  12. #12
    Junior Member Cait's Avatar
    Joined
    Mar 2007
    From
    MI, unfortunately
    Posts
    32

    Red face

    Ok thanks you guys are lifesavers!

    Now lets see what problems i have with the next section! XD but that will be for another post....
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Rational Expressions
    Posted in the Algebra Forum
    Replies: 2
    Last Post: November 11th 2010, 07:33 PM
  2. Rational Expressions
    Posted in the Algebra Forum
    Replies: 5
    Last Post: October 23rd 2010, 03:27 PM
  3. Rational Expressions and Radical Expressions
    Posted in the Algebra Forum
    Replies: 16
    Last Post: July 9th 2009, 09:29 PM
  4. Rational expressions
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 5th 2007, 08:23 PM
  5. Rational Expressions- NEED HELP PLZ
    Posted in the Algebra Forum
    Replies: 9
    Last Post: March 1st 2007, 05:48 PM

Search Tags


/mathhelpforum @mathhelpforum