Multistep measurement problems i need questions 6,7 & 8 hope you can me !

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.

1mile equals approximately 1.6 kilometers. which best approximates the number of miles in 6 kilometers?

What is the area of the triangle 10 13 12