Answer:
Step-by-step explanation:
The mean (or average) of a set of numbers can be found with the following formula:

For this problem, we have five numbers, so we add them together and divide by 5:



Answer:
Step-by-step explanation:
25b * (3a² - 1) = 25b * 3a² - 25b * 1
= 75ba² - 25b
Distributive law upon subtraction:
a(x - y) = ax - ay
The answer to your question would be 6!
Move X to the other side with the 30.