Thread: Congruence equation

Just want confirmation.

15x=5 in Z63.

I used a theorem in my book to conclude that this has no solution because letting d be the gcd(15,63)=3, d does not divide 5. Is this true?

Originally Posted by JaysFan31

Just want confirmation.

15x=5 in Z63.

I used a theorem in my book to conclude that this has no solution because letting d be the gcd(15,63)=3, d does not divide 5. Is this true?

The gcd(63,5)=1
Thus,
15x=5(mod 63)
Reduces to,
5x=1(mod 63)