# Math Help - Bit of a rush

1. ## Bit of a rush

How does this work

d = inverse of 13 mod 12

what is d

2. Originally Posted by jzon
How does this work

d = inverse of 13 mod 12

what is d

You need an $x$ such as,
$13x\equiv 1\mod 12$
Which can be rewritten as,
$(13-12)x\equiv 1\mod 12$
Thus,
$x\equiv 1\mod 12$