Question

If f(x) = 6 - 5x, what is f(x)^-1? (check attachment)

Answer 1

f(x) = 6-5x

y = 6-5x .... replace f(x) with y

x = 6-5y .... swap x and y; solve for y

x+5y = 6

5y = 6-x

y = (6-x)/5

$f^{-1}(x) = \frac{6-x}{5}$ ... replace y with the inverse function notation

Answer: Choice D.