2. Prove that there is no integer π such that 7|4π^2β3
3. Find the remainder by division by 7 of 99999999.
4. Find the remainder in the division by 17 of 15!
5. Let π be a prime. Show that for all integerππ we have that π|ππ+(πβ1)!π and π|π+(πβ1)!ππ.