show the solution so that i understand
2007-02-19 00:06:09 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
15 cannot be an inverse of any number mod 9
because 15 and 9 are not relatively prime.
A true inverse of 7 mod 9 is 4, because 7*4 = 1(mod 9).
2007-02-19 01:59:59 · answer #1 · answered by steiner1745 7 · 1⤊ 0⤋
I don't think it is an inverse. Are you sure of your question? Two numbers are inverses of each other if you can multiply them together and get the number 1. In modulo 9 arithmetic, you must reduce the answer to a number between 0 and 8 by getting the remainder after dividing by 9.
15 multiplied by 7 gives 105.
Modulo 9, that is equal to 6, not 1, so I can't see how 15 can be an inverse of 7.
2007-02-19 00:16:21 · answer #2 · answered by Gnomon 6 · 0⤊ 0⤋
2
2007-02-19 00:08:40 · answer #3 · answered by Anonymous · 0⤊ 1⤋
7 modulo 9 = 0 rem. 7
inv. 1/7
2007-02-19 01:16:32 · answer #4 · answered by Anonymous · 1⤊ 1⤋