1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Mean congruence homework

  1. Nov 29, 2003 #1
    i need help with this question

    893x=266(mod 2432) ,= mean congruence

    fisrt i find gcd(893,2432)=19
    then i need to find u,v for 893u-2432v=19
    the u and v i found is -49 and -18
    but the answer here in my book is 79 and 29
    after calculating, i found that both the answer are correct. my question is how to get 79 and 29?

  2. jcsd
  3. Nov 29, 2003 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    If the problem is "893x=266(mod 2432)"

    how could the answer be "u= 79 and v= 29" OR "u= -49 and v= -18"?

    Where did u and v come from? What happened to x?
  4. Nov 29, 2003 #3
    first i use this method to find the gcd of (893,2432).that is
    from here i found the gcd is 19
    then 19 can divide 266, therefor it has a solution

    if i reverse all the step above, i will get
    from this 893x=266(mod2432)i can change to 893x-2432y=266
    therefor this formula 893(-49)-2432(-18)=19 should multiply by 14 to get the formula same as above. with this i can get x later, but the problem is that i get -49 and -18 and not 79 and 29.
  5. Nov 29, 2003 #4
    I think the answer in the book is wrong. Because
    They do not work. Why do you think they are correct?

    (Why does it make these spaces before mod? How can I TeX it better?)
    Last edited: Nov 29, 2003
  6. Nov 29, 2003 #5
    the formula i get is 893u - 2432v = 19. with euclidean algorithm i get 893(-49) - 2432(-18) = 19. i get negative numbers (u,v) = (-49,-18). how can i change it to a positive numbers like (u,v) = (79,29)?
  7. Nov 30, 2003 #6
    Sorry, I can only help you if you answer my question.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Mean congruence homework
  1. || meaning (Replies: 6)

  2. Two Congruence questions (Replies: 11)