Question

If f(x) = 2x – 4,find f-1(x)
Answer

Answer 1

f-1(x) = (x+4) / 2

Explanation:

given f(x) = 2x – 4

let y = f(x) and rearrange to express x in terms of y

y = 2x – 4 (add 4 to each side)

y + 4 = 2x (divide both sides by 2)

(y+4) / 2 = x (rearrange)

x = (y+4) / 2

f-1(y) = (y+4) / 2

hence

f-1(x) = (x+4) / 2