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Maths factorising help?!

  • 22-11-2015 12:26PM
    #1
    Kelly090
    Registered Users, Registered Users 2 Posts: 80 ✭✭


    Anyone out there who is any way good at maths willing to help me here.
    How do you factorise:
    1) x^4+x
    2) a^2+b^2-2ab
    Thanks so much in advance to anyone who replies!


Comments

  • #2
    Peregrine
    Moderators, Education Moderators Posts: 26,417 Mod ✭✭✭✭Peregrine


    Both of the terms in the first one have a common factor of x.

    The second one is a perfect square.


  • #3
    Kelly090
    Registered Users, Registered Users 2 Posts: 80 ✭✭Kelly090


    Hi guys need some help here...
    Is (a-b)^2 = (a-b)(a-b) or (a-b)(a+b)
    How do you know which one it is?!
    Thanks so much to anyone who replies!


  • #4
    skippy1977
    Registered Users, Registered Users 2 Posts: 284 ✭✭skippy1977


    This is the reverse of 'factorising'. Factorising is putting terms into brackets. You want to expand the brackets. (a-b)^2=(a-b)(a-b). Then multiply out. Anything squared is multiplied my itself so (a-b) squared is (a-b) times (a-b).

    You may be mixing up with the factorisation of a^2-b^2 which is (a-b)(a+b)?


  • #5
    Kelly090
    Registered Users, Registered Users 2 Posts: 80 ✭✭Kelly090


    So guys I'm struggling a bit with these factorising questions here, how would you answer:
    x^3 + y^3+ 3x +3y


  • #6
    NOS3
    Registered Users, Registered Users 2 Posts: 265 ✭✭NOS3


    There is two different types of factorising here. Difference of 2 cubes and HCF. Tackle them separately first. :)


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  • #7
    skippy1977
    Registered Users, Registered Users 2 Posts: 284 ✭✭skippy1977


    NOS3 wrote: »
    There is two different types of factorising here. Difference of 2 cubes and HCF. Tackle them separately first. :)

    Sum of Cubes


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