How do you change y-4=3(x+3) into slope-intercept form

Me find the measure to side a and the process to solve the problem you appreciate it : )

Four airplanes carrying a total of 400 passengersarrive at the detroit airport. the airplanes carry, respectively,50, 80, 110, and 160 passengers.a) one of the 400 passengers is selected uniformly at random.let x denote the number of passengers that were on theairplane carrying the randomly selected passenger. find var(x)for x as given in the problemb) one of the 4 airplane drivers is also selected uniformly atrandom. let y denote the number of passengers on the chosen driver’s airplane. find var(y) for y as given in the problem

1. find the area of the unshaded square 2. find the area of the large square 3. what is the area of the frame represented by the shaded region show