Which expression is equivalent to 2(x2-1)+3x(x-4)?

When y’all answer can y’all explain too !

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?

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)