The inverse of 3 modulo 7 is
A. -1
B. -2
C. -3
D. -4
Answer:A
The inverse of 3 modulo 7 is
A. -1 B. -2 C. -3 D. -4
Explanation: By using the Euclidean algorithm, 7 = 2*3 + 1. From this we see that -2*3 + 1*7 = 1. This show that -2 is an inverse.