What is the first step to solve the following system of equations using substitution? x - y = 12
2x - y = 12
A.) Add the two equations together.
B.) Solve the first equation for x.
C.) Multiply the first equation by 2.
D.) Divide the second equation by 2.

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