The height of a triangle is 4 m less than its base. the area of the triangle is 48m^2 what is the length of the base 48=x(x-4

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?