Help someone I just need the answer

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?

Factor the polynomial by its greatest common monomial factor.

The equation of a parabola is given. y=18x2+4x+20 what are the coordinates of the focus of the parabola?