Results 1 to 6 of 6

Math Help - Is this a perfect-square trinominal?

  1. #1
    Newbie
    Joined
    Dec 2011
    Posts
    9

    Is this a perfect-square trinominal?

    Problem is 27x^2-117x-90

    So should I take the GCF of 9 out first?

    9(3x^2-13x-10)

    Or do I look at the problem before that and see if it is a perfect-square?

    Thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Dec 2011
    Posts
    9

    Re: Is this a perfect-square trinominal?

    when I work it out i get 9(3x+2)(x-5)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,617
    Thanks
    1581
    Awards
    1

    Re: Is this a perfect-square trinominal?

    Quote Originally Posted by bashemgud View Post
    Problem is 27x^2-117x-90
    The {\bf\color{red}-}90 tells you it is not a square trinominal.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Dec 2011
    Posts
    7

    Unhappy Re: Is this a perfect-square trinominal?

    Quote Originally Posted by Plato View Post
    The {\bf\color{red}-}90 tells you it is not a square trinominal.

    can you tell me why?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    -1
    e^(i*pi)'s Avatar
    Joined
    Feb 2009
    From
    West Midlands, England
    Posts
    3,053
    Thanks
    1

    Re: Is this a perfect-square trinominal?

    Quote Originally Posted by moonwoo View Post
    can you tell me why?
    The constant term in a perfect square is always positive. Expand (a+b)^2 and note the sign of b^2
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    11,519
    Thanks
    1404

    Re: Is this a perfect-square trinominal?

    Quote Originally Posted by bashemgud View Post
    when I work it out i get 9(3x+2)(x-5)
    This is correct. Clearly this is not a perfect square...
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. perfect square trinomial/square of binomial
    Posted in the Algebra Forum
    Replies: 2
    Last Post: March 3rd 2011, 04:02 PM
  2. Replies: 1
    Last Post: July 21st 2010, 02:24 PM
  3. perfect square
    Posted in the Algebra Forum
    Replies: 2
    Last Post: April 28th 2010, 08:57 AM
  4. N! is never a perfect square
    Posted in the Number Theory Forum
    Replies: 7
    Last Post: December 9th 2009, 09:41 AM
  5. Perfect Square
    Posted in the Algebra Forum
    Replies: 1
    Last Post: June 24th 2009, 07:16 AM

Search Tags


/mathhelpforum @mathhelpforum