:

given the following information:

u = {x|x is a natural number less than 20}

a = {x| x is an odd natural number less than 16}

b = {x|x is a prime number greater than 5}

start by writing these sets out in roster method.

then you first want to find a', the complement of a.

a', represents all the elements in the universal set that are not in a. another way to look at it is u - a, or the universal set minus the set a.

next, you will find the union of a' and the set b. this means to combine all of elements in sets a' and b.