Digital Logic - Boolean Algebra

A Boolean function is given as $f = (\bar{u} + \bar{v} + \bar{w} + x). (\bar{u} + \bar{v} + w + x). (\bar{u} + v + \bar{w} + x). (\bar{u} + v + w + x)$ The simplified form of this function is represented by

Simplified form of the Boolean function $F(P,Q,R,S) = \overline{P}\overline{Q} + \overline{P}QS + \overline{P}Q\overline{R}\overline{S} + P\overline{Q}\overline{R}\overline{S}$ is

The Boolean expression AB + AC + BC simplifies to