Can someone help me with inverses?

Question

anonymous · Answer

attachment

godlovesme · Answer

sorry idk :(

anonymous · Answer

$$f(x)= \frac{ x+4 }{ 2 }$$

anonymous · Answer

@geerky42 @Jhannybean

godlovesme · Answer

@SolomonZelman  can  u help ASAP

geerky42 · Answer

Let $y = f(x)$.

To find $f^{-1}(x)$, just swap x and y to each other, then isolate y.

That y is$f^{-1}(x)$.

geerky42 · Answer

So in your problem, $f(x)=y=\dfrac{x+4}{2}\Longrightarrow x = \dfrac{y+4}{2}$

Isolate y.

anonymous · Answer

when I first tried answering it i got$$f ^{-1}(x)= 2x-4$$ but when I put that in my calculator it was wrong

anonymous · Answer

ok

geerky42 · Answer

$2x-4$ is correct?

anonymous · Answer

no

jhannybean · Answer

1. label f(x) as y
2. Switch the x and the y 
3. Solve for y
4. rewrite y as f^{-1} (x)

anonymous · Answer

I tend to go wrong when I try to solve for y...

geerky42 · Answer

Well, in attachment, you just insert what a, b, c, and d are equal to.

anonymous · Answer

but I have to use the function to make them inverses.

geerky42 · Answer

Well, we did. You let $a = 4,~b=2$ and since $g(x)=f^{-1}(x) = 2x-4$, you have $c=2,~d=4$

Is that what you put in? 4, 2, 2, 4 for a, b, c, d respectively?

anonymous · Answer

yes. I've got it now, I thought that the functions needed to equal the same thing.