Outline strategy for 1.: , so use Fermat's little theorem to find mod 7, mod 11 and mod 13. Then use the Chinese remainder theorem to piece the results together.

For 2., you can't "solve" something that isn't an equation. But if you want toverifythat then use a similar strategy to 1., namely factorise 35 (and check that the result holds mod 5 and mod 7).