Question

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

Answer 1

$$
y = log_2(x+4)
$$ Saying \(f^{-1}(3)\) is basically saying \(y = 3\)
$$
3 = log_2(x+4) \\
2^3 = 2^{(log_2(x+4))} \\
2^3 = x+4 \\
x = 2^3 - 4 = 8 - 4 = 4
$$
And if we check in the original function then \(f(4)\) is basically:
$$
y = log_2(4+4) = log_2(8) = 3
$$

Answer 2

thank you

Answer 3

Sure np =)