Question

help with inverse functions!!

Answer 1

solve for x in terms of f(x)

Answer 2

sqrt(y-5) + 1

and y-5 >= 0 when y >= 5

so you did fine

Answer 3

ah great, thank you! these questions confuse me, so i am never sure if i get the correct answer after ive solved. can i post the others on this question? im taking the practice test but they dont tell me the correct answers when i get them wrong.

Answer 4

we can work a few, prolly not all tho

Answer 5

explain the answer you want to choose, just so i can see if your thought process is sane enough

Answer 6

haha okay sounds good, thank you! i will post the ones i come across that im unsure of.

Answer 7

k

Answer 8

i cant recall how to solve these..i know there are only a few steps though im just stuck

Answer 9

if X is the domain of f, and Y is the range of f

then Y is the domain of inverse, and X is range of inverse

Answer 10

all in inverse does, is take the values of a range and gives back the value that got you there.

Answer 11

hmm okay. would that leave the answer to be A? im still not quite sure

Answer 12

what is the domain of f?

Answer 13

is it f^-1?

Answer 14

you are given f, what is the domain of f? what values of x can you use in the defined function?

Answer 15

okay so you are given x-9/21-4x

Answer 16

y = (x-9)/(21-4x)

y(21-4x) = x-9

21y -4yx = x-9

21y + 9 = x +4yx

21y + 9 = x(1 +4y)

(21y + 9)/(1 +4y) = x

y cannot be -1/4, since it zeroes out the bottom

so B fits the bill right?

Answer 17

okay so you solve for x? yes that would make B the answer

Answer 18

i think B has an error tho, in the print

Answer 19

other than that, its the best for the buck

Answer 20

okay thanks! so to solve it you move it around so that x is all alone. but how is it that you determine the domain from that?

Answer 21

domain is all usable values

Answer 22

1 + 4y is in the denominator, we cant devide by 0 so

1 + 4y = 0 when y=-1/4

Answer 23

is there a value of x that makes f equal to -1/4?

-1/4 = (x-9)/(21-4x)

-1(21-4x) = 4(x-9)

4x-21 = 4x-9

so when does 21 = 9? never