Let f(x) = 7x - 13. Find f-1(x). I'll medal

Question

anonymous · Answer

To find the inverse:

Replace f(x) with y
Switch x's and y's, so put x where y is and x where y is.
Solve for y
Replace y with f^-1(x)

dangerousjesse · Answer

Take the integral:
 integral $$\int\limits(7 x-13) dx $$
Integrate the sum term by term and factor out constants:
 $$ =  7 \int\limits x d x-13 \int\limits 1 d x $$
The integral of x is x^2/2:
  $$=  (7 x^2)/2-13 \int\limits 1 dx $$
The integral of 1 is x:
Answer:
$$   =  (7 x^2)/2-13 x+constant  $$

dangerousjesse · Answer

Ignore that first random "integral"

anonymous · Answer

Integration...why?

anonymous · Answer

He's looking for inverse, not area.

dangerousjesse · Answer

Because that was the most simple way of answering this question.. Holy crap. I completely misunderstood this question.

anonymous · Answer

Hahahaaaa

dangerousjesse · Answer

I wasted so much time on that -.-

anonymous · Answer

$$f(x) = 7x-13 ~~~ \implies y = 7x-13$$

$$x = 7y-13 $$

Solve for y now

$$y = \frac{ x+13 }{ 7 } \implies f ^{-1}(x) = \frac{ x+13 }{ 7 }$$