(-1,-7) and slope of 2

If you could answer these your a life saver

The vertices of a triangle are a(7.5), b(4,2), and c19. 2). what is

Determine the required value of the missing probability to make the distribution a discrete probability distribution. x p(x) 3 0.23 4 ? 5 0.51 6 0.08 p(4) = nothing  (type an integer or a decimal.)