Someone help please i hate geometry

Carl's candies has determined that a candy bar measuring 3 inches long has a z-score of +1 and a candy bar measuring 3.75 inches long has a z-score of +2. what is the standard deviation of the length of candy bars produced at carl's candies?

If a company produces x units of an item at a cost of $35 apiece the function c=35x is a of the total production costs

Multiply and simplify. (x - 4) (x^2 – 5x – 6) i will mark brainliest if your answer is right. show how you got the answer. if your answer is correct but does not show how you got the answer you will not be marked brainliest.