Help me with these questions show your work !

The average number of vehicles waiting in line to enter a parking lot can be modeled by the function f left parenthesis x right x squared over 2 left parenthesis 1 minus x right parenthesis endfraction , where x is a number between 0 and 1 known as the traffic intensity. find the rate of change of the number of vehicles waiting with respect to the traffic intensity for the intensities (a) xequals0.3 and (b) xequals0.6.

One integer is 8 times another. if the product is 72, then find the integers

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?