Results 1 to 3 of 3

Thread: HW Question Factoring

  1. #1
    Junior Member
    Joined
    Oct 2008
    Posts
    26

    HW Question Factoring

    I don't know how to go on about solving this...

    IT asks Use factoring to solve the equation for the real values of the variable

    y^4 - 26y^2 + 25 = 0

    I know how to factor but this one is throwing me off...
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Aug 2007
    Posts
    144
    Hi civiliam,

    We have $\displaystyle y^4-26y^2+25=0$ . Notice that this is a quadratic in $\displaystyle y^2$ , thus if we let $\displaystyle w=y^2$ we can re-write the equation as $\displaystyle w^2-26w+25=0$ . Now this is a fairly routine quadratic since $\displaystyle w^2-26w+25=(w-25)(w-1)=0$ and thus we can conclude that $\displaystyle w=25$ , $\displaystyle w=1$ . Since $\displaystyle w=y^2$ we can say $\displaystyle y^2=25$ , $\displaystyle y^2=1$ and therefore the four roots of the equation are $\displaystyle \pm 5$ , $\displaystyle \pm 1$ .

    Hope this helps.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Oct 2008
    Posts
    26
    thank you so much that's perfect
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Need help factoring a question.
    Posted in the Algebra Forum
    Replies: 4
    Last Post: Apr 20th 2011, 10:06 PM
  2. Factoring Question
    Posted in the Algebra Forum
    Replies: 3
    Last Post: Apr 23rd 2010, 03:12 PM
  3. Factoring question
    Posted in the Algebra Forum
    Replies: 5
    Last Post: Jan 31st 2010, 01:33 PM
  4. Question on Factoring
    Posted in the Algebra Forum
    Replies: 9
    Last Post: May 30th 2008, 10:55 AM
  5. Factoring question
    Posted in the Algebra Forum
    Replies: 3
    Last Post: Mar 27th 2007, 09:58 AM

Search Tags


/mathhelpforum @mathhelpforum