Which model is NOT a function?

Which of the following expressions is equal to 2x^2+8

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.

What number should be added to the expression x^2+3x+ in order to create a perfect square trinomial? 3/2 3 9/4 9