Results 1 to 7 of 7

Math Help - er quadratic fatorisation?

  1. #1
    Newbie
    Joined
    Dec 2008
    From
    York, Yorkshire
    Posts
    18

    Exclamation er quadratic fatorisation?

    Any help on this would be appreciated...

    write  4x^2 - 24x + 27 in the form  a(x-b)^2+c

    i have thought about factorising but it wants the  + c which just confuses me

    thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member TheMasterMind's Avatar
    Joined
    Dec 2008
    Posts
    155
    Quote Originally Posted by RubbishAtMaths View Post
    Any help on this would be appreciated...

    write  4x^2 - 24x + 27 in the form  a(x-b)^2+c

    i have thought about factorising but it wants the  + c which just confuses me

    thanks

    y=4x^2-24x+27

    y-27=4x^2-24x

    y-27=4(x^2-6x)<br />

    y-27=4(x^2-6x+9-9)

    y-27=4(x-3)^2-4(9)

    y=4(x-3)^2-9

    Edit: Moo beat me to it!
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Moo
    Moo is offline
    A Cute Angle Moo's Avatar
    Joined
    Mar 2008
    From
    P(I'm here)=1/3, P(I'm there)=t+1/3
    Posts
    5,618
    Thanks
    6
    Hello,
    Quote Originally Posted by RubbishAtMaths View Post
    Any help on this would be appreciated...

    write  4x^2 - 24x + 27 in the form  a(x-b)^2+c

    i have thought about factorising but it wants the  + c which just confuses me

    thanks
    4x^2-24x+27=4(x^2-6x)+27=4[(x-3)^2-3^2]+27
    =4(x-3)^2-4 \cdot 3^2+27=4(x-3)^2-9
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Dec 2008
    From
    York, Yorkshire
    Posts
    18
    how do you go about completing the square?

    *thanks moo!
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Member TheMasterMind's Avatar
    Joined
    Dec 2008
    Posts
    155
    Quote Originally Posted by RubbishAtMaths View Post
    how do you go about completing the square?

    *thanks moo!
    \
    Last edited by TheMasterMind; January 8th 2009 at 01:39 PM. Reason: wish to delete
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Newbie
    Joined
    Nov 2008
    Posts
    12

    could u just explain this a little please

    i understand most of it just not the bit i have pointed out
    Quote Originally Posted by TheMasterMind View Post
    y=4x^2-24x+27

    y-27=4x^2-24x

    y-27=4(x^2-6x)<br />

    y-27=4(x^2-6x+9-9)

    y-27=4(x-3)^2-4(9)
    I dont Understand what u did with the -27 and how u got the -4(9)???
    thanks
    y=4(x-3)^2-9

    Edit: Moo beat me to it!
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Member TheMasterMind's Avatar
    Joined
    Dec 2008
    Posts
    155
    Quote Originally Posted by adeshSB View Post
    i understand most of it just not the bit i have pointed out
    y-27=4(x-3)^2-9(4)

    y-27=4(x-3)^2-36

    y=4(x-3)^2-36+27

    y=4(x-3)^2-9
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. quadratic?
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: February 10th 2010, 05:05 AM
  2. Replies: 10
    Last Post: May 6th 2009, 09:52 AM
  3. Replies: 1
    Last Post: June 12th 2008, 09:30 PM
  4. Quadratic Eq.
    Posted in the Algebra Forum
    Replies: 2
    Last Post: May 27th 2008, 06:54 PM
  5. Quadratic
    Posted in the Number Theory Forum
    Replies: 1
    Last Post: April 13th 2007, 07:15 PM

Search Tags


/mathhelpforum @mathhelpforum