1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Factoring with the quadratic formula

  1. Oct 1, 2006 #1
    I have a huge headache and I can't understand why this works... I am reviewing the quadratic formula so that I can solve trig questions, but I am stuck on this one part...

    The point is to factor [tex]x^2+2x-1[/tex]

    I ( and the textbook ) use the quadratic formula to get the roots of it and come up with

    [tex]-1\pm\sqrt{2} [/tex]

    How do I use this to factor into [tex](x+1-\sqrt{2})(x+1+\sqrt{2})[/tex]?

    I remember the quadratic formula as being more useful for solving quadratics where 1 side =0... I don't remember factoring with it! Can someone help? I would try to figure it out on my own but my head is spinning and I am under time pressure at this point. Thanks alot guys.

    I really do appreciate the help that I recieve on these boards. :smile:
    Last edited: Oct 1, 2006
  2. jcsd
  3. Oct 1, 2006 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    The quadratic formula gives you 2 roots r1 and r2 you then get the factors from

    (x - r1) (x - r2) You then need to check your work by multiplying the 2 factors to ensure that you get back your starting quadratic.
  4. Oct 2, 2006 #3
    Thankyou Integral!! You helped me remember :)
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Factoring with the quadratic formula
  1. Quadratic Formula (Replies: 5)

  2. Factoring a quadratic (Replies: 7)

  3. Quadratic formula (Replies: 2)

  4. Factoring quadratics (Replies: 9)

  5. Factoring a Quadratic (Replies: 15)