if you still are unsure, i will go through an example:
let x=2, i.e y(2) = 4 + ln2, so the point (4+ln2, 2) is on our original function, now this point corresponds to (2, 4 + ln2) on the inverse function as i just
swap x and y values as above. So your question f^-1(2) is basically the point (2...