Question

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

Answer 1

f⁻¹(x) stands for the invers of function f(x). The inverse of f(x) is equal to x. We need to solve for x.

solve for x
f(x) = 2x + 2
2x + 2 = f(x)
2x = f(x) - 2
  x = $\dfrac{f(x)-2}{2}$
f⁻¹(x) = $\dfrac{x-2}{2}$

Determine the value of f⁻¹(x) when x = 4
f⁻¹(x) = $\dfrac{x-2}{2}$
f⁻¹(4) = $\dfrac{4-2}{2}$
f⁻¹(4) = $\dfrac{2}{2}$
f⁻¹(4) = 1
When x = 4, the value of f⁻¹(x) is equal to 1