Question

Find the inverse of the function f(x) = 2x – 4.

Answer 1

Let y = 2x − 4. Swap x and y and solve for y:

x = 2y − 4
2y = x + 4
y = (x + 4)/2

So f⁻¹(x) = (x + 4)/2 = x/2 + 2 (domain and range: all real numbers).