Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Factoring polynomials

  1. Aug 30, 2006 #1
    Factoring polynomials(2nd problem)

    Factor:

    36(2x-y)^2 - 25(u-2y)^2

    Having trouble where to start...should I expand out?
     
    Last edited: Aug 31, 2006
  2. jcsd
  3. Aug 30, 2006 #2
    Is that u and u, or is that suppose to be an x
     
  4. Aug 30, 2006 #3

    StatusX

    User Avatar
    Homework Helper

    You can start by noticing that that is the difference of two squares.
     
  5. Aug 31, 2006 #4
    Yeah its a U, got it figured out now.

    I have another one that i'm having trouble with:

    (a^2 - ab)^2 -8b^2(a^2 - ab) + 12b^4

    I tried factoring the a^2-ab out

    = (a^2-ab)[-8b^2 + (a^2-ab)] + 12b^4

    Tried a couple methods none really worked out...what should be my next step? Should i factor a^2-ab to a(a-b)?
     
    Last edited: Aug 31, 2006
  6. Sep 1, 2006 #5

    StatusX

    User Avatar
    Homework Helper

    Do you know how to factor ax^2+bxy+cy^2? Because this expression is in that form.
     
  7. Sep 2, 2006 #6
    Make

    (a^2 - ab)=X
    AND
    b^2=Y

    Therefore, X^2-8xy+12y^2

    Then solve and sub back in.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook