Past exam of the year 1 of the computer science course of the University of Oxford / 2015 / Discrete mathematics, continuous mathematics, and probability (resit) / 1 / c / i / Solution

Take every complement of a set relative to $\mathcal{U}$. By set difference, De Morgan's laws, and distribution of set intersection over set union,Here the middle term is the empty set, since a set and its complement of a set are disjoint.