Answer:
The answer to the union of the two sets is:

Explanation:
Since they are asking for an "OR" condition, we need to find the set of solutions for each inequality, and then use the union of those two sets.
First inequality:

so this is the set of all real numbers smaller than or equal to -3 (visualize the numbers on the number line to the left of -3 and including -3 itself)
Second inequality:

So, this sets consists of all real numbers smaller than or equal to -4 (visualize the numbers on the number line to the left of -4 and including -4 itself.
Then, when we do the union of these two sets, we get:

since the number -4 is located to the left of -3 on the number line, so the set defined by the second inequality is in fact a subset of the one defined by the first inequality.