Question

Let f(x) = 7x - 13. Find f-1(x)

@jigglypuff314

Answer 1

alright :)
so inverse means that you switch the x for a y and a y for the x

so x = 7y - 13 solve for y :)

Answer 2

+13 to both sides?

Answer 3

yes :)

Answer 4

13x = 7y?

Answer 5

are you looking for the inverse or -1?

Answer 6

im not sure this is what the problem says

Answer 7

funny, i did not see an option A

Answer 8

y= 7x-13 y+13 = 7x x = (y+13)/7 now to find inverse function just replace x and y y= (x+13)/7 so your inverse function is
f−1(x)=x+137
got this ?

Answer 9

yes

Answer 10

how would you solve this?
Let f(x) = x2 - 3x - 7. Find f(-3).
would it be -3 = -3(2) - -3(-3)?

Answer 11

mmm f(-3) means x = -3
so (-3)^2 - 3(-3) - 7

Answer 12

To find the inverse:

Replace f(x) with y
Switch x's and y's, so put x where y is and x where y is.
Solve for y
Replace y with f^-1(x)

Answer 13

9 - -9 - 7 = 11?

Answer 14

I actually just wrote this on someone else's post, and copy pasted here, since it fits the question, anyways sorry to intrude jiggly, continue.

Answer 15

lol it's fine iambatman xP I'm kinda lost...
but yeah 11 turtle

Answer 16

How're you lost :o

Answer 17

:) good job turtle

Answer 18

thank you:) what about Let f(x) = 2x - 6. Solve f-1(x) when x = 2
would i do 2 = 2(2) - 6?

Answer 19

first get f-1(x)
so x = 2y - 6 solve for y

Answer 20

+ 6 on both sides?

Answer 21

yep :)

Answer 22

6x = 2y do i divide 6 by 2?

Answer 23

mmmm
x + 6 = 2y divide both sides by 2

Answer 24

would it be 3?

Answer 25

not quite...
mmm they want you to find x= 2 right?
so 2+6 = 2y solve for y ?

Answer 26

oh ok so would it be 4?

Answer 27

correct :)

Answer 28

ok thank you last question for the night i promise Let f(x) = 2x + 2. Solve f-1(x) when x = 4.

Answer 29

we've done a couple of f-1(x) type problems now, can you try setting it up yourself this time? :)

Answer 30

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

Answer 31

-4 = 8 +2 add 2 to both sides -2 = 8 now divide -4?

Answer 32

I'm confused with where you're going with this :/
x = 2y + 2 when you flip the x and y
then x = 4
so 4 = 2y + 2 solve for y

Answer 33

would it be 2?

Answer 34

mmm not quite :)

Answer 35

thank you so much for your help!!! i have to go to dinner thank you:)

Answer 36

I'm glad I could help :)