When you are finding an inverse of a function, you switch the x and the y and solve for the new y. Our y = 5x, when switching x and y will be x = 5y. Now we have to find the new y. Dividing both sides by 5 we get
. The really cool thing about functions that are inverses of each other is that their coordinates, (x, y) are switched to. If a point (1, 2) is on f(x), the point (2, 1) is on the inverse. And they always reflect through the line y = x. Just a bit of info.