9asquared-3asquared-3a+15divided by 3a+2

Do xuan nam isgoing to invest $1000 at a simple interest rate of 4% how long will it take for the investment to be worth $1040?

Let x have probability generating function gx (s) and let un generating function u(s) of the sequence uo, u1, satisfies p(x > n). show that the (1- s)u(s) = 1 - gx(s), whenever the series defining these generating functions converge.

State how many imaginary and real zeros the function has. f(x) = x3 - 20x2 + 123x - 216