Question

Algebra help

Answer 1

Let f(x) = 2x + 2. Solve f−1(x) when x = 4.

Answer 2

can you help?

Answer 3

Okay, So We Know That X = 4. So, We Have to Plug It In.

Answer 4

Y = 2x +2

Answer 5

Swich It To:
2x = Y - 2

Answer 6

so we just switch the x and y?

Answer 7

Just Wait

Answer 8

we still didn't plug in the 4

Answer 9

We Switch The F and the y.
Here Is A Pic:

Answer 10

where did you get 1/2?

Answer 11

and how did the 2 turn into a 1? I'm confused right now

Answer 12

you first need to find the inverse of f(x)

let f(x) = y
y = 2x + 2
now solve for x

Answer 13

Wouldn't you flip the x and y?
x=2y+2?

Answer 14

no

Answer 15

y = 2x + 2
2x = y - 2
x = ?

Answer 16

y-1=x

Answer 17

No you need to divide the y by 2 as well as the - 2

Answer 18

y/2 - 1 = x

Answer 19

x = (1/2)y - 1

now we write f-1(x) for x and x for y

f-1(x) = (1/2)x - 1

Answer 20

- thats the inverse

now plug in x = 4 into this and you'll get f-1(4)

Answer 21

wait i'm so confused right now

Answer 22

we need the value of f-1(x) when x = 4
so replace the x in f-1(x) by 4 and simplify

Answer 23

so 1/2y -1 = f-1(4)?

Answer 24

No we have found the inverse function
f-1(x) = (1/2)x - 1 right?

Answer 25

to find its value when x = 4 its

(1/2)*4 - 1 - replacing the x by 4

Answer 26

I'm still confused to where you got 1/2

Answer 27

oh wait nvm it was originally y instead of x

Answer 28

yes

we replaced y by x - the inverse is a function of x.

Answer 29

2-1 = 1
don't know why I said -1

Answer 30

1 s correct

Answer 31

Can I try the other one on my own and you correct me if it's wrong?

Answer 32

ok

Answer 33

These are not too difficult. Practice makes perfect.