Results 1 to 3 of 3

Thread: Is 19(mod729) - x(mod729), the same as 19-x(mod729)?

  1. #1
    Member
    Joined
    Mar 2009
    Posts
    184
    Thanks
    1

    Is 19(mod729) - x(mod729), the same as 19-x(mod729)?

    Hi all,

    Is 19(mod729) - x(mod729), the same as 19-x(mod729)?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    11,152
    Thanks
    731
    Awards
    1
    Quote Originally Posted by sirellwood View Post
    Hi all,

    Is 19(mod729) - x(mod729), the same as 19-x(mod729)?
    Yes.

    -Dan
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    12,028
    Thanks
    848
    Hello, sirellwood!

    $\displaystyle \text{Is }\,19\text{ (mod 729)} - x\text{ (mod 729)},\,\text{ the same as }\,19-x \text{ (mod 729) }\,?$

    $\displaystyle 19\text{ (mod 729)\, means: }\:19 + 729a\quad\text{(19 plus a multiple of 729)}$

    $\displaystyle x\text{ (mod 729)\, means: }\:x + 729b \quad (x\text{ plus a multiple of 729)} $


    Then: .$\displaystyle 19\text{ (mod 729)} - x\text{ (mod 729)}$

    . . $\displaystyle =\;(19 + 729a) - (x + 729b)$

    . . $\displaystyle =\;\underbrace{19 - x + 729(a-b)}_{(19-x)\text{ plus a multiple of 729}}$

    . . $\displaystyle =\;19-x\text{ (mod 729)}$

    Yes!

    Follow Math Help Forum on Facebook and Google+

Search Tags


/mathhelpforum @mathhelpforum