Results 1 to 3 of 3

Math Help - quick question, need bit of help

  1. #1
    Member
    Joined
    Mar 2007
    Posts
    80

    quick question, need bit of help

    looking at an example i jotted off the white board today,

    C = 550 - 10X + (1/2)X^2

    R = 75X - (1/2)X^2


    Then Ive written P= R - C which is...

    P = 85X - X^2 - 550

    but i just jotted the answer, i get how ive got 85x but cant remember how to get the 1/2 x^2 into just -x^2

    if someone could go throught the question that would be great,

    Thank you.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    A riddle wrapped in an enigma
    masters's Avatar
    Joined
    Jan 2008
    From
    Big Stone Gap, Virginia
    Posts
    2,551
    Thanks
    12
    Awards
    1
    Quote Originally Posted by bobchiba View Post
    looking at an example i jotted off the white board today,

    C = 550 - 10X + (1/2)X^2

    R = 75X - (1/2)X^2


    Then Ive written P= R - C which is...

    P = 85X - X^2 - 550

    but i just jotted the answer, i get how ive got 85x but cant remember how to get the 1/2 x^2 into just -x^2

    if someone could go throught the question that would be great,

    Thank you.
    75x-\frac{1}{2}x^2-\left(550-10x+\frac{1}{2}x^2\right)=

    75x{\color{red}-\frac{1}{2}x^2}-550+10x{\color{red}-\frac{1}{2}x^2}=

    85x{\color{red}-x^2}-550
    Last edited by masters; October 30th 2008 at 01:01 PM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,405
    Thanks
    1328
    Quote Originally Posted by bobchiba View Post
    looking at an example i jotted off the white board today,

    C = 550 - 10X + (1/2)X^2

    R = 75X - (1/2)X^2


    Then Ive written P= R - C which is...

    P = 85X - X^2 - 550

    but i just jotted the answer, i get how ive got 85x but cant remember how to get the 1/2 x^2 into just -x^2

    if someone could go throught the question that would be great,

    Thank you.
    -\frac{1}{2}x^2- \frac{1}{2}x^2= -(\frac{1}{2}+ \frac{1}{2})x^2= -x^2
    Because 1/2+ 1/2= 1!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. quick question
    Posted in the Calculus Forum
    Replies: 3
    Last Post: August 23rd 2009, 08:28 PM
  2. Quick question
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: September 30th 2008, 04:09 PM
  3. Quick question
    Posted in the Algebra Forum
    Replies: 2
    Last Post: March 13th 2008, 03:51 PM
  4. Quick Question - SPP, CPP, TSP
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: December 17th 2007, 08:49 PM
  5. Quick's quick question
    Posted in the Number Theory Forum
    Replies: 22
    Last Post: July 9th 2006, 04:38 PM

Search Tags


/mathhelpforum @mathhelpforum