What is the value of 19+5a^4-3b^2 when a = 2 and b=4

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

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

Solve each quadratic equation by factoring and using the zero product property. 14x - 49 = x^2