Can someone help me understand this? Give awnsers in simplest form:

a. (1/2 - 1/3) x (1/4 + 1/5 divided by 1/6)

b. 6 squared divided by 3/2 x (1 3/4 x √4)

c. 7/8 x 1 1/4 divided by (3/16 - 1/8)

d. 9/8 x (2/5 + 3/7 x 1/3 + 3/5) x 4​

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.