# Question: prove by mathematical induction that for ngt1 n ...

###### Question details

prove by mathematical induction that for n>=1 , n : integer

a) (11^n) -1 is a multiple of 10

b) (5^n) + 3 is divisible by 4

c) (5^2n) - 1 is a multiple of 8

d) (9^n) - 3 is a multiple of 6

e) (n^2) + 2n is divisible by 8

f) (3^n) + (7^n) is divisible by 10