Question

Can someone please help me with these question. I really don't know how to do them
1. f-1(4) when f(x) = 3x minus 4, all over 5
2. y + 10 = 2y + 1

Answer 1

1) if you solve \(\dfrac{3x-4}{5}=4\) what do you get for x?

Answer 2

you get 3x=16 right?

Answer 3

I ask for x, not 3x

Answer 4

x =??

Answer 5

so x=16/3

Answer 6

simplify more, it is x =8, ok?

Answer 7

wait how does x=8?

Answer 8

oh, I am sorry, not 8, you are correct, 16/3

Answer 9

dont you have to do something with the -1 in f-1(4)?

Answer 10

f^-1(4)

Answer 11

oh no!! you confuse me, we don't get that number
oh boy!
\(\dfrac{3x-4}{5}=4\rightarrow 3x-4=20\rightarrow 3x = 24 \rightarrow x =8\) hahaha...

Answer 12

ok??

Answer 13

i thought u had to do something with the inverse of -1. or is that just there.

Answer 14

yeah, be patient, please, now I do it

Answer 15

\(f(\color{red}{x})=4\\f^{-1}(4) =\color{red}{x}\)
you have \(f(\color{red}{8})=4\\f^{-1}(4) =\color{red}{8}\)
right?

Answer 16

oh i see

Answer 17

:)

Answer 18

so the answer is 8 overal

Answer 19

yup, and don't forget the way how to get the answer.

Answer 20

i got it thanks :)

Answer 21

:)