I would rewrite the question then show how you got your answer
That depends. If you have a finite data set, you would add up all the points you have and divide by the total count.
Or, if you are working with pure distributions, the mean is the same as the expected value of the corresponding random variable.
Suppose you have a discrete random variable

with a given probability mass function

, then the mean is given by

which would mean you take all the possible probability for the event that

, multiply each by that

, and add them together.
If the distribution is continuous, say a random variable

that has probability distribution function

over some support

, then the mean is
Answer: 8x^2+2x+3 where ^2 means the 2 is an exponent.
<span>A postulate becomes a theorem when it is proven by a series of logical steps to a valid outcome. Typically, a postulate is a statement that is presumed to be true without proof, whereas a theorem is a true statement that can be proven</span>