 The operation has an opposite. The opposite of addition is subtraction and the inverse of a function is exactly that. It's the opposite of the function. It undoes the function and returns you to the input. So for this function machine, the inverse would add 2 and divide by 5. So 13 add 2 is 15 and divide by 5 is 3. Where f of x means our function, f to the minus 1 of x, is the inverse of the function. Let's have a look at how I found the inverse of the function to be x plus 2 divided by 5. Maybe some of you can just see that from our function machine. But sometimes it gets quite tricky so we have got a nice simple process to follow. Start by writing the function as y equals. Switch your x and y's around so they just switch places. Rearrange to make y the subject and there you found the inverse. So write it as f to the minus 1 of x. Here's one for you to do. I'll leave this example on screen so you can follow the steps. Pause the video, find the inverse function and click play when you're ready. How did you get on? You may have also got f to the minus 1 of x equals 4 divided by 3x plus 2 thirds. This is just because you did your rearranging a little bit differently. So here's another one for you to do but this time without any steps on screen. Don't worry about this little bit for now just ignore it. It's just telling us that the domain is any value of x that's bigger than 3. Pause the video, find the inverse of the function and click play when you're ready. Did you get root x plus 3? So there we have inverse functions. Just remember to switch the x and y's around and then rearrange to become y equals.