Can someone help me solve this problem?

If f(x)= 3x+6 which of the following is the inverse of f(x)

What were mkh company's cash flows from (for) operating activities in 20x1? $(180,300) $233,100 $268,200 $279,400?

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?