2- y + 6 + 4y + 4 + 7y

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?

How many ordered pairs of positive integers satisfy xy=32?

Which expression is equal to (f+g)(x)?