How do i find the inverse? I need to find the inverse of f(x) = 2x- 8? How do i do it.

Question

anonymous · Answer

like solving 
$$2x-8=20$$ add 8 
divide by 2
so inverse is 
$$f^{-1}(x)=\frac{x+8}{2}$$

anonymous · Answer

Where did you get the 20 from

amistre64 · Answer

a common strategy is to swap the places of x and f(x) and rearrange the setup to solve for f(x)

anonymous · Answer

is that the right answer though

amistre64 · Answer

if you want something rigorous, you might wanna google it and pull it off one of those .edu sites

amistre64 · Answer

intuitively; the inverse swaps y=x positions

anonymous · Answer

i made up the 20, idea is that the inverse solves for the variable when you know the output. so method is "add 8, divide by 2"
you can always write 
$$2x-8=y$$
$$2x=y+8$$
$$x=\frac{y+8}{2}$$ so inverse is 
$$f^{-1}(x)=\frac{x+8}{2}$$ or as amistre said you can swap x and y and write 
$$2y-8=x$$
$$2y=x+8$$
$$y=\frac{x+8}{2}$$ same thing

anonymous · Answer

thanks