With the associative property, it does not matter which order you multiply numbers in. The answer to 4*5 is the same answer as 5*4. This works with more than two numbers as well. The associative property of addition also works this way.
In this question, it is important to watch where the parentheses are placed.
ANSWER: C) 4(2a * 5) = (2a * 5) * 4. Multiplying 4 to the left or the right of the set of parentheses will result in the same answer.
You cannot divide first because in equations you need to isolate the variable, which means subtracting first. The outcome will be different if you change the order.