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Homework Help: Discrete math and proof

  1. Sep 3, 2006 #1
    Please can someone help me with this problem.

    show that a,b,c are real numbers and a#0, then there is a unique solution of the equation ax+b=c.

    the uniqueness of the solution is my problem.
    Thank you
  2. jcsd
  3. Sep 3, 2006 #2


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    Science Advisor

    If the uniqueness is the problem, then suppose there were two solutions, x1 and x2. Since they are solutions to that equation, you must have, of course, ax1+ b= c and ax2+ b= c. Subtracting one equation from the other, a(x1- x2)= 0. What does that tell you?
  4. Sep 3, 2006 #3

    That's right. we can ay that x1=x2. so unique soltuion
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