Results 1 to 7 of 7

Math Help - Not sure if I got this problem right, can someone verify?

  1. #1
    Newbie
    Joined
    Sep 2010
    Posts
    9

    Not sure if I got this problem right, can someone verify?

    (3xy^-2)^2(-2x^-4y)^3 / (x^-3y^2)^-3


    I tried to check problem and of course it says my answer is wrong, but I can't figure out why!

    I got:

    -72y^5/x^19
    Last edited by gustahfan; September 14th 2010 at 08:03 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor undefined's Avatar
    Joined
    Mar 2010
    From
    Chicago
    Posts
    2,340
    Awards
    1
    Quote Originally Posted by gustahfan View Post
    (3xy^-2)^2(-2x^-4y)^3/(x^-3y^2)^-3


    I tried to check problem and of course it says my answer is wrong, but I can't figure out why!

    I got:

    -72y^5/x^19
    Hmm I get what you get.

    \dfrac{(3xy^{-2})^2(-2x^{-4}y)^3}{(x^{-3}y^2)^{-3}} =(3xy^{-2})^2(-2x^{-4}y)^3(x^{-3}y^2)^3

    =(9x^2y^{-4})(-8x^{-12}y^3)(x^{-9}y^{6})=(9)(-8)x^{2-12-9}y^{-4+3+6}=\dfrac{-72y^5}{x^{19}}

    What does your book say? (Or is it that your solution is getting rejected by an automatic checker? I have not worked with those, but perhaps it has to do with typesetting or putting the answer in a form the computer will recognize.)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member Educated's Avatar
    Joined
    Aug 2010
    From
    New Zealand
    Posts
    424
    Thanks
    11
    \dfrac{(3xy^{-2})^2 \times (-2yx^{-4})^3}{(x^{-3} \times y^2)^-3}

    Is this your equation? If it is, then \frac{-72y^5}{x^{19}} is correct.

    I don't know if you meant -2x^(-4y) or -2x^-4 * y.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Sep 2010
    Posts
    9
    Thank you Undefined and Educated. Yes the way that undefined wrote it out was correct. I tried the [tex] formatting but it came out funky. I was checking it on mathway.com. And it came out with something like:

    9y^2/{x^19}.

    Again thanks for the replies, I knew I was right!
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor undefined's Avatar
    Joined
    Mar 2010
    From
    Chicago
    Posts
    2,340
    Awards
    1
    Quote Originally Posted by gustahfan View Post
    Thank you Undefined and Educated. Yes the way that undefined wrote it out was correct. I tried the [tex] formatting but it came out funky. I was checking it on mathway.com. And it came out with something like:

    \frac 9y^2/{x^19}.

    Again thanks for the replies, I knew I was right!
    Glad your problem is solved. Regarding LaTeX, you can double click on the LaTeX above to see how it was done. Some useful commands are \frac and \dfrac, also important are braces {}.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Senior Member Educated's Avatar
    Joined
    Aug 2010
    From
    New Zealand
    Posts
    424
    Thanks
    11
    Best way to learn LaTeX is to read the tutorial.
    LaTeX Tutorial

    I find that Wolfram|Alpha is a good maths computational website. Just remember to use brackets.
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Junior Member RHandford's Avatar
    Joined
    Sep 2010
    From
    N.E. Lincolnshire
    Posts
    70
    Hi All

    This is also a helpful graphical interface to LaTeX, the script output can be copied and posted to site.
    It can be found here
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. okay the last verify problem i have problems with
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: October 12th 2011, 08:34 PM
  2. Please verify
    Posted in the Algebra Forum
    Replies: 2
    Last Post: January 25th 2010, 06:55 PM
  3. Can someone verify this L'Hospital problem
    Posted in the Calculus Forum
    Replies: 2
    Last Post: October 11th 2009, 08:52 AM
  4. Replies: 5
    Last Post: April 30th 2009, 03:18 AM
  5. Help to verify & solve this determinants problem!
    Posted in the Advanced Algebra Forum
    Replies: 2
    Last Post: March 12th 2007, 12:26 PM

/mathhelpforum @mathhelpforum