Results 1 to 6 of 6
Like Tree2Thanks
  • 1 Post By hedi
  • 1 Post By Plato

Math Help - Number of Solutions help

  1. #1
    Member
    Joined
    Oct 2012
    From
    san francisco
    Posts
    92

    Number of Solutions help

    Hey I need some help with this problem:

    How many solutions in natural numbers are there to the equation a + b + c + d = 12 where a and b are odd?

    I am hoping someone can show me the steps on how to go about doing this so I will understand how to do this problem thanks.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Oct 2012
    From
    israel
    Posts
    109
    Thanks
    14

    Re: Number of Solutions help

    substitute a=2A+1,b=2B+1,c=2C+1 d=2D+1 and consider the number of non negative integer solutions of A+B+C+D=4.
    Thanks from zzephod
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Oct 2012
    From
    san francisco
    Posts
    92

    Re: Number of Solutions help

    Ok so I substituted and ended up with
    A+B+C+D = 4 so the possible solutions for a b c d is 1?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Oct 2012
    From
    israel
    Posts
    109
    Thanks
    14

    Re: Number of Solutions help

    Now the number of solutions is the bonomial coefficient C(4+4-1,4-1)=C(7,3)=35
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,712
    Thanks
    1642
    Awards
    1

    Re: Number of Solutions help

    Quote Originally Posted by hedi View Post
    substitute a=2A+1,b=2B+1,c=2C+1 d=2D+1 and consider the number of non negative integer solutions of A+B+C+D=4.
    You should note that the OP requires only a & b be odd.
    Look at the coefficient of x^{12} in this expansion.
    Thanks from gfbrd
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Member
    Joined
    Oct 2012
    From
    san francisco
    Posts
    92

    Re: Number of Solutions help

    Thanks Plato
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. NUmber of solutions
    Posted in the Discrete Math Forum
    Replies: 5
    Last Post: November 14th 2010, 04:52 AM
  2. Number of solutions of x^2 + xy + y^2 = 27 in Q
    Posted in the Number Theory Forum
    Replies: 3
    Last Post: September 27th 2010, 12:37 AM
  3. Number of solutions for z^n = a
    Posted in the Calculus Forum
    Replies: 3
    Last Post: May 25th 2010, 10:32 AM
  4. number of solutions
    Posted in the Trigonometry Forum
    Replies: 3
    Last Post: May 3rd 2009, 06:16 AM
  5. Number of solutions for x^2+x=0 mod n
    Posted in the Number Theory Forum
    Replies: 2
    Last Post: October 9th 2008, 11:52 AM

Search Tags


/mathhelpforum @mathhelpforum