Expanding and factorising

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  1. zed963's Avatar
    1 23-04-2012  17:20
    • Overlord in Training
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    Expanding and factorising
    I have a question

    100(p+1/2)^2-4(q+1/2)^2

    How do I solve this question.

    I know that I should square the bracket.

    But i'm not too sure about the 1/2 squared. I think it becomes 1/4
  2. Bobifier's Avatar
    2 23-04-2012  17:24
    • TSR Demigod
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    Re: Expanding and factorising
    This is not a question, it is an expression. What are you trying to do with it?
  3. zed963's Avatar
    3 23-04-2012  17:28
    • Overlord in Training
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    Re: Expanding and factorising
    (Original post by Bobifier)
    This is not a question, it is an expression. What are you trying to do with it?

    factorise
  4. Contrad!ction.'s Avatar
    4 23-04-2012  17:30
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    Re: Expanding and factorising
    (Original post by zed963)
    factorise
    a(b+c)+d(b+c)=(a+d)(b+c)

    Does this help?

    EDIT: No it doesn't, because I've been a total plonker and misread the q as another p.
    Last edited by Contrad!ction.; 23-04-2012 at 17:37.
  5. zed963's Avatar
    5 23-04-2012  17:31
    • Overlord in Training
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    Re: Expanding and factorising
    (Original post by Contrad!ction.)
    a(b+c)+d(b+c)=(a+d)(b+c)

    Does this help?
    the value in the bracket is different not the same for both
  6. GreenLantern1's Avatar
    6 23-04-2012  17:45
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    Re: Expanding and factorising
    (Original post by Contrad!ction.)
    a(b+c)+d(b+c)=(a+d)(b+c)

    Does this help?

    EDIT: No it doesn't, because I've been a total plonker and misread the q as another p.
    BTW the vid in your sig only looks good cuz she tlaks fast.

    She is wrong bout the very first thing with .2222

    She adds to the left side, yet she doesn't do the same on the RHS.

    It should be X+2 not 2X; she has multiplied by 2 on one side and added 2 on the other.

    That is wy her proof that the proof is wrong, is in fact wrong!
  7. Contrad!ction.'s Avatar
    7 23-04-2012  17:50
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    Re: Expanding and factorising
    (Original post by GreenLantern1)
    BTW the vid in your sig only looks good cuz she tlaks fast.

    She is wrong bout the very first thing with .2222

    She adds to the left side, yet she doesn't do the same on the RHS.

    It should be X+2 not 2X; she has multiplied by 2 on one side and added 2 on the other.

    That is wy her proof that the proof is wrong, is in fact wrong!
    And at the end she says 'April Fools', it was a piss take.

    (Original post by zed963)
    the value in the bracket is different not the same for both
    Oh yeah, sorry. I sort of skimread, the p and q looked the same. Argh.

    Back to the question - yeah, \left( \frac{1}{2} \right) ^2 = \frac{1}{4}

    Do you know how to multiply brackets?
  8. around's Avatar
    8 23-04-2012  17:53
    • Vengeful, Imperial Overlord of The Student Room
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    Re: Expanding and factorising
    difference of two squares?
  9. steve2005's Avatar
    9 23-04-2012  17:58
    • TSR Demigod
    • Location: LONDON
    Re: Expanding and factorising
    (Original post by zed963)
    I have a question

    100(p+1/2)^2-4(q+1/2)^2

    How do I solve this question.

    I know that I should square the bracket.

    But i'm not too sure about the 1/2 squared. I think it becomes 1/4
    Why do you not learn from the advice you have been given?

    The question should be "Simplify the expression" or "Factorise the expression"

    I posted a fairly similar answer in your other thread last night.
  10. zed963's Avatar
    10 23-04-2012  18:08
    • Overlord in Training
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    Re: Expanding and factorising
    (Original post by steve2005)
    Why do you not learn from the advice you have been given?

    The question should be "Simplify the expression" or "Factorise the expression"

    I posted a fairly similar answer in your other thread last night.

    My bad
  11. nm786's Avatar
    11 23-04-2012  18:11
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    Re: Expanding and factorising
    (Original post by zed963)
    I have a question

    100(p+1/2)^2-4(q+1/2)^2

    How do I solve this question.

    I know that I should square the bracket.

    But i'm not too sure about the 1/2 squared. I think it becomes 1/4
    yes, 1/2^2=1/4 because 1*1=1 and 2*2=4

    So, here's the answer:
    100(p^2+1/4)-4(q^2+1/4) =100p^2+25-4q^2-1 =100p^2-4q^2+24
  12. nm786's Avatar
    12 23-04-2012  18:14
    • Overlord in Training
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    Re: Expanding and factorising
    (Original post by zed963)
    x
    i'm guessing this is gcse maths?
  13. steve2005's Avatar
    13 23-04-2012  18:14
    • TSR Demigod
    • Location: LONDON
    Re: Expanding and factorising
  14. zed963's Avatar
    14 23-04-2012  18:27
    • Overlord in Training
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    Re: Expanding and factorising
    (Original post by nm786)
    yes, 1/2^2=1/4 because 1*1=1 and 2*2=4

    So, here's the answer:
    100(p^2+1/4)-4(q^2+1/4) =100p^2+25-4q^2-1 =100p^2-4q^2+24
    So in order to factorise this it becomes 4(25p^2-q^2+6) =4(5p+q+2)(5p-q+3q)
  15. steve2005's Avatar
    15 23-04-2012  18:33
    • TSR Demigod
    • Location: LONDON
    Re: Expanding and factorising
    (Original post by nm786)
    yes, 1/2^2=1/4 because 1*1=1 and 2*2=4

    So, here's the answer:
    100(p^2+1/4)-4(q^2+1/4) =100p^2+25-4q^2-1 =100p^2-4q^2+24
    It might be the required answer or it might not. What was the question?

    Was the question " simplify " or was the question " factorise ", if the latter, then you answer needs more work.

    Edit The following is wrong because it does not follow the previous working.

    100(p^2+1/4)-4(q^2+1/4) =100p^2+25-4q^2-1 =100p^2-4q^2+24
    Last edited by steve2005; 23-04-2012 at 18:39.
  16. steve2005's Avatar
    16 23-04-2012  18:37
    • TSR Demigod
    • Location: LONDON
    Re: Expanding and factorising
    (Original post by nm786)
    yes, 1/2^2=1/4 because 1*1=1 and 2*2=4

    So, here's the answer:
    100(p^2+1/4)-4(q^2+1/4) =100p^2+25-4q^2-1 =100p^2-4q^2+24

    This contains serious errors

    (p + 1/2 )^2 does not equal what you have.
  17. TenOfThem's Avatar
    17 23-04-2012  18:40
    • No --- I am a Newbie --- Honest
    Re: Expanding and factorising
    (Original post by zed963)
    I have a question
    100(p+\frac{1}{2})^2 - 4(q+\frac{1}{2})^2

    This is just like the one I showed you how to do yesterday

    You wil not expand the brackets

    It is difference of 2 squares
  18. steve2005's Avatar
    18 23-04-2012  18:43
    • TSR Demigod
    • Location: LONDON
    Re: Expanding and factorising
    (Original post by zed963)
    I have a question

    100(p+1/2)^2-4(q+1/2)^2

    How do I solve this question.

    I know that I should square the bracket.

    But i'm not too sure about the 1/2 squared. I think it becomes 1/4
    There are several methods of factorising the expression.




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  19. nm786's Avatar
    19 23-04-2012  18:46
    • Overlord in Training
    • Posts: 2,540
    Re: Expanding and factorising
    (Original post by steve2005)
    This contains serious errors

    (p + 1/2 )^2 does not equal what you have.
    so what does it equal to?
  20. TenOfThem's Avatar
    20 23-04-2012  18:50
    • No --- I am a Newbie --- Honest
    Re: Expanding and factorising
    (Original post by nm786)
    so what does it equal to?
    Well

    (p+\frac{1}{2})^2


    Is certainly not

    p^2 + \frac{1}{4}


    So it is up to the OP to see where he has gone wrong
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