If A = x is an even integer, B = {5, 6, 7, 8}, list the elements of the set A U B

First of all, what is an integer?

Integers are numbers such as - 7, - 4, 0, 5, 16 ... etc ...

This means that even integers are numbers such as:

-4, - 2, 0, 2, 4, 6, 8, 10 ... etc ...

Which means that:

AUB={ ..., - 4, - 2, 0, 2, 4, 5, 6, 7, 8, 10, 12, 14, ... }

This is because:

The union " U " of two sets must contain all the numbers from both sets, providing they aren't duplicated.