Q6. Using the definition of 1 = y mod N, justify the rule I = I'mod N, Y = y' mod N = IX mod N xy= Q8. Give an "efficient method to compute the nth Fibonacci number Fn mod N for fixed N. Explain the method and analyze the running time. Also comment on the correctness of the method. Q10. Prove of disprove, if a has an inverse modulo N then N has an inverse modulo a. Q12. Give an efficient" algorithm to compute the least common multiple of two n bit numbers a, b. What is the running time of your algorithm as a function of n