What do you mean by solving problem 1?

What do you mean by the "first part"? Are you talking about problem 1 or 2?

This can be done, for example, using Karnaugh maps. I got AC' + CD + A'B'D. It requires some time to explain the solution, so please tell us what ways of simplifying Boolean expressions you have studied and what you have tried.2. Simplify the Boolean expression

A C ' + B ' D + A ' C D + A B C D