Question

Let f(x) = 7x - 13. Find f-1(x).

Answer 1

@Hero

Answer 2

Let y = f(x), then y = 7x - 13
swap x and y:

x = 7y - 13

Now isolate y

Answer 3

so x + 13 =7y

Answer 4

Okay, but you still have one step left in order to isolate y.

Answer 5

In order for y to be isolated, it has to be alone on one side.

Answer 6

like that?

Answer 7

Okay, yes

Answer 8

then I don't get what's after that

Answer 9

What happens if you ever have 7/7?

Answer 10

well then it's canceling each other out

Answer 11

Exactly. The last step is to replace y with \(f^{-1}(x)\)

Answer 12

so it's