If f(x) = log₂ (x + 4), what is f^-1(3)?
0, 2, 4, 8

Solution:

It is given that function

f(x) = log₂ (x + 4)

y = log₂ (x + 4)

It can be written as

2^y = x + 4

x = 2^y - 4

So f^-1(x) = 2^x - 4

We have to find f^-1(3)

f^-1(3) = 2³ - 4

By further calculation

= 8 - 4

= 4

Therefore, f^-1(3) is 4.

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If f(x) = log₂ (x + 4), what is f^-1(3)?

Summary:

If f(x) = log₂ (x + 4), f^-1(3) is 4.