Question

Given the function f(x) = log2(x + 6), find the value of f^−1(3).

Answer 1

I really need help with understanding this.

Answer 2

Answer Choices:
a. f−1(3) = 2
b. f−1(3) = 3
c. f−1(3) = 9
d. f−1(3) = 18

Answer 3

@zepdrix help please

Answer 4

@SkaterBoyShawn can you help me?

Answer 5

yes

Answer 6

okay good

Answer 7

\[f^{-1}(3)=a \implies f(a)=3 \\ \text{ so you need to solve } \log_2(a+6)=3 \text{ for } a \]

Answer 8

@freckles in my notes it was saying how i had to find the inverse function or something like that

Answer 9

let me solve it 1sec

Answer 10

ok @SkaterBoyShawn

Answer 11

You can find the inverse function then plug in 3
or you can just solve the equation above for a

Answer 12

ugh im still confused

Answer 13

i think i got the answer

Answer 14

on what part?

Answer 15

like why \[f^{-1}(3)=a \implies f(a)=3 ? \\ \text{ or on solving } \log_2(a+6)=3 \text{ for } a?\]

Answer 16

how? @SkaterBoyShawn and @freckles everything like what do you do with log2?

Answer 17

you want to write in the equivalent exponential form

Answer 18

recall
\[\log_b(x)=y \implies b^{y}=x\]

Answer 19

i dont get any of this at all. Math is my weakest subject

Answer 20

so you don't know how to compare
\[\log_b(x)=y \text{ to } \log_2(a+6)=3 \\ \text{ then use that } \log_b(x)=y \implies b^y=x \\ \text{ to write } \log_2(a+6)=3 \text{ in exponential form }\]?

Answer 21

what is in place of the b?
in place of the x?
in place of the y?