# Math Help - Modules

1. ## Modules

I have this sample problem but i dont understand the transition from step 3 to 4

1. 11x +8 =16 (mod 26)
2. 11x=8
3. (11^-1)*11x=(11^-1)*8
4. x=19*8=152=100=48=22

thanks

2. Originally Posted by laucoyne

I have this sample problem but i dont understand the transition from step 3 to 4

1. 11x +8 =16 (mod 26)
2. 11x=8
3. (11^-1)*11x=(11^-1)*8
4. x=19*8=152=100=48=22

thanks
The multiplicative inverse of 11 in mod 26 is 19. That is to say
$19 \cdot 11 \equiv 1~\text{(mod 26)}$

-Dan