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Math Help - Need help factoring these equations!

  1. #1
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    Exclamation Need help factoring these equations!

    I have a couple of questions actually, I have a test tommorow on factoring from standard form PLEASE HELP ! It would be much appreciated.
    so here are the problems I'm having difficulties with.
    a)6h^2 -17+ 12 b)24a^2b^3 + 9a^2 + b^2 + 18a^3b^2

    c) 4k^2 + 36k + 81 d) 4p^2q - 8p^2 - q +2

    Question 2 : 9x^2 + Kx +144 - This is a perfect square trinomial what is the value of k? explain.

    Factor :
    1) a^2 - 2a + 1 - b^2 + 2bc - c^2
    THANK YOU SO MUCH TO ANYONE THAT ANSWERS!!!
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  2. #2
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    Quote Originally Posted by farfromover View Post

    Question 2 : 9x^2 + Kx +144 - This is a perfect square trinomial what is the value of k? explain.


    For this to be a perfect square then 9x^2 + Kx +144 = (3x+12)(3x+12)

    Expand the RHS and you will find K

    You really need to show some workings so we know where to help. Giving you answers in the 11th hour before a test is not what you need. You need to learn how to apply the techniques of factorisation.
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  3. #3
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    Hello, farfromover!

    1) Factor: . a^2 - 2a + 1 - b^2 + 2bc - c^2

    We have two "groups": . (a^2-2a+1) - (b^2-2bc+c^2)

    Factor the groups: . (a-1)^2 - (b-c)^2 . . . . difference of squares

    . . . . =\;\bigg[(a-1)-(b-c)\bigg]\,\bigg[(a-1) + (b-c)\bigg]

    . . . . =\;(a-1-b+c)\,(a-1+b-c)

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  4. #4
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    thank you!
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  5. #5
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    so is K equal to 0?
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  6. #6
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    Quote Originally Posted by farfromover View Post
    so is K equal to 0?
    Show me the expansion.
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  7. #7
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    Quote Originally Posted by pickslides View Post
    For this to be a perfect square then 9x^2 + Kx +144 = (3x+12)(3x+12)

    Expand the RHS and you will find K

    You really need to show some workings so we know where to help. Giving you answers in the 11th hour before a test is not what you need. You need to learn how to apply the techniques of factorisation.
    Expansions: 9x^2 + 36x + 36x + 144
    = 9^x + 72 + 144
    Oh so its equal to 72.
    can the 72 be negative also?
    Thank you
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  8. #8
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    Quote Originally Posted by farfromover View Post
    can the 72 be negative also?
    Yes, this will give (3x-12)(3x-12)
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  9. #9
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    thank you so much, and what is this one its tricky :
    9 - (5n-1) ^2

    I tried letting x = (5n-1) but when i check it its incorrect
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  10. #10
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    Differnece of two squares says a^2-b^2 = (a-b)(a+b)

    9 - (5n-1) ^2 = 3^2 - (5n-1) ^2 = (3-(5n-1))(3+(5n-1))= \dots

    simplify to finish..
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