Question

What is the inverse of f(x) = 3x + 4?

Answer 1

Think of it this way: what does f do? It multiplies by 3 then subtracts 4. So the inverse does the opposite in the reverse order; i.e. adds 4, then divides by 3.

So the inverse function is f ˉ¹(x) = (x+4)/3

Answer 2

That's not what I got...
The way i learned was to swap your x's and y's in the equation (since the inverse of a graph is one reflected over the identity line, aka swapping the x's and y's)
So you'd have x=3y+4, then solve for y
-3y=4-x
y=(x-4)/3

Answer 3

ummm Heres another way to put it, Basically, you are switching the 'x's and the 'y's, and then isolating to solve for x:

x= 3y-4

3y= x+4

y= (x+4)/3

Therefore y^-1 (that's how you write inverse) =(x+4)/3

Answer 4

I prefer the 1st one i did, its just easier in my opinion, there's always a chance to do it more then 1 way :P

Answer 5

The original there is wrong, it should say x=3y+4 not -4