Let f(x) = 2x + 2. Solve f^-1(x) when x = 4

Solution:

Given f(x) = 2x + 2

Let y = 2x + 2

⇒ y - 2 = 2x

⇒ x = y - 2/2 = y/2 - 1

if f(x) = y/2 - 1, then the inverse function is given as

⇒ f^-1(x)= x/2 - 1

⇒ If x = 4, f^-1(4) = 4/2 - 1

⇒ f^-1(4) = 2 - 1 = 1

Let f(x) = 2x + 2. Solve f^-1(x) when x = 4

Summary:

If f(x) = 2x + 2 then the value of f^-1(x) when x = 4 is 1.