A function is given:

f(x) = 3x + 12

a. Determine the inverse of this function and name it g(x).
b. Use composite functions to show that these functions are inverses.
c. Evaluate f(g(–2)). Explain: What is the domain?
WILL GIVE BRAINLIEST PLEASE EXPLAIN WELL
100 POINTS

Cassie is traveling 675 miles today to visit her brother and his family. so far, she has stopped for gas three times. at the first stop, she put in 7.1 gallons of gas and paid $23.79. at her second stop, she put in 5.8 gallons of gas and paid $19.08. and, at the third stop, 6.6 gallons and paid $20.39. at which stop did casey pay the most for gas?

Me get the answer and explain to me the steps to solve it would be greatly appreciated : )

Acarpool service has 2,000 daily riders. a one-way ticket costs $5.00. the service estimates that for each $1.00 increase to the one-way fare, 100 passengers will find other means of transportation. let x represent the number of $1.00 increases in ticket price. choose the inequality to represent the values of x that would allow the carpool service to have revenue of at least $12,000. then, use the inequality to select all the correct statements. the maximum profit the company can make is $4,125.00. the maximum profit the company can make is $15,625.00. the price of a one-way ticket that will maximize revenue is $12.50. the price of a one-way ticket that will maximize revenue is $7.50.