Question

Prove that 5^31–5^29 is divisible by 100.

Answer 1

5^31-5^29

=5^29(5^2-1)

=5^29(25-1)

=5^29(24) ...a

100=5^2x4 ...b

Divide a by b

5^29(24) / 5^2 x 4

=5^27 x 6

This, 5^31-5^29 is divisible by 100.