I want you to remember this rule:
When multiplying or dividing two different integers that have different signs which are: + (positive sign) and - (negative sign). You get a negative number
However, if you are multiplying or dividing two different integers but they have the same signs. You end up with a positive number
Also multiply are associative, means that they can change the numbers around but they still end up in the same answer
So in this question p x (-q) = (-p) x q = -pq (they put a bracket in the negative number so the question could be easier to be reconize)
We can make:
p = 3
q = 4
So: 3 x -4 = -12
-3 x 4 = -12
-3(4) = -12 (it's a different way to write multiply)
You can see here using the facts that I gave up there supports that
p x (-q) = (-p) x q = -pq