PLEASE I NED HELP ASAP LOOK AT THE PICTURE

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

How can you tell when x and y are not directly proportional?

Anut store normally sells cashews for? $4.00 per pound and peanuts for? $1.50 per pound. but at the end of the month the peanuts had not sold? well, so, in order to sell 40 pounds of? peanuts, the manager decided to mix the 40 pounds of peanuts with some cashews and sell the mixture for $2.00 per pound. how many pounds of cashews should be mixed with the peanuts to ensure no change in the? profit?