# Number theory equations

## Homework Statement

Solve the following equations positive integers:

(i) a!+b!+c!=d!

(ii) a!+b!=25*c!

(iii)a!=b^2

## Homework Equations

For the first two one , i have no idea how to begin . But the third one I may use Bertrand's Postulate some where. Could anyone give me some ideas??