Two integers, a and b, have a greatest common factor of 1. If a =12 and b is greater than 35 but no more than 40, what is the value of b?

If y varies directly as x2 and y=6 when x=6, find the constant of variation.

Due to a packaging error, 4 cans labeled diet soda were accidentally filled with regular soda and placed in a 12 pack carton of diet soda. two cans were randomly selected from this 12 pack. what is the probability that both cans were regular soda?

How is this equation completed? i cannot find any examples in the book.