Answer
$(M\cap N) \cup R = R$; M and N are disjoint sets. (M $\cap$ N) and R are also disjoint sets.
Work Step by Step
RECALL:
(1) The symbol $\cup$ represents union of sets which lists down in a set the combined elements of the given sets.
(2) The symbol $\cap$ represents intersection of sets which lists down in a set the elements common to the given sets.
Use (2) to obtain:
$M \cap N = \emptyset$
Use (1) above, and the fact that the empty set has no elements, to obtain:
$(M\cap N) \cup R = \emptyset \cup R = R$
Two sets that have no elements in common are disjoint sets.
