Required detailed solution to probability math exercise

Long story short - I suck at math and I need some bonus points in a course I was forced to take. Need a detailed solution to a probability exercise: The shooter with each successful shot earns 5 points and with each failed shot loses 2 points. Chance of hitting the target is equal 0,7 each time. The shooter takes 3 shots. [login to view URL] distribution function F(x) and distribution table of points earned with each shot. 2. Calculate probability of average and dispersion when P(x<10), P(-5<x≤8), P(x>0)