Question

If f(x) = log3 (x + 1), what is f−1(2)?
1
8
10
27

Answer 1

We are asked in the problem to determine f−1(2) given the function f(x) = log3 (x + 1). The first step is to determine the inverse of f(x).

f-1(x) :

y = log3(x+1)
x= log3(y+1)
3^x = y +1
y = 3^x - 1
if x = 2 
y = 8

Answer 2

Answer:

Option B. 8

Step-by-step explanation:

Given function is $f(x)=log_{3}(x + 1)$

Now we have to find the value of $f^{-1}(x)$.

Since $f(x)= y=log_{3}(x+1)$

$3^{y}=(x + 1)$

Now for $f^{-1}(x)$

we will replace x by y.

$3^{x}=y + 1$

$y=3^{x}-1$

$f^{-1}(x)=3^{x}-1$

Now we put the value of x = 2

y = 3²- 1 = 9-1 = 8

Therefore $f^{-1}(2)=8$ is the answer.