Question

I HAVE AN EXAM TOMORROW, PLEASE HELP ME!!!
f(x)= 2x+3
what is f^-1
(basically I think they're asking what is the inverse)

Answer 1

dont u just switch x and y then to find the inverse?

Answer 2

Exactly. They are asking for the inverse. Do you know how to do that?

Answer 3

ok um let me just send you guys the actual question

Answer 4

Okie.

Answer 5

here:

Answer 6

you are correct in swapping x and y

then you need to make y the subject of the eqution

Answer 7

I did that, and I got A, not D

Answer 8

Like if you want a better look at the graphs:

Answer 9

A:

Answer 10

B:

Answer 11

C:

Answer 12

D:

Answer 13

E is none of the above

Answer 14

well inverse functions are reflected in the line y = x

so for f(x) = 2x + 3

the inverse is\[f^{-1}(x) = \frac{x -3}{2}\]

Answer 15

If you think it's A. You got the inverse wrong.

Let's look at solving the inverse again

y=2x+3

switch x and y

x=2y+3

2y=x-3

divide by 2

y^-1=(x-3)/2

Answer 16

ohhhhhhhhhhhhhhh, and again, I AM A FREAKING IDIOT!!!!!!!

Answer 17

Now if you graph that...it should be straight foward

Answer 18

so the keys, y- intercept -3/2 slope 1/2

Answer 19

ok i get it now, thanks so much :) :) :)

Answer 20

Or if you aren't allowed to use a calculator

y=2x+3

Plug random x values and get a bunch of (x,y) coordinates.

Inverse is just the coordinates reversed

For example

If a coordinate for y=2x+3 is -5,-7

the inverse coordinate is -7,-5