Question

…………..HELP……………………………..

Answer 1

Answer:

C

Step-by-step explanation:

Let f(y)=x.

$x=\frac{1}{3}-\frac{1}{21}y \\ \\ x-\frac{1}{3}=-\frac{1}{21}y \\ \\ y=-21x+7 \\ \\ f^{-1}(x)=-21x+7$