I need to find the inverse of this function

f(x)=9x+7

please show steps. The answer I got is not one of the multiple choices I have.
The answer I got is f^-1 (x)=1/9x-7/9

1 answer

y = 9x-7
y+7 = 9x
x = (y+7)/9

so, f-1(x) = (x+7)/9