Answer:
1/3x - 3
Step-by-step explanation:
To find the inverse, we exchange x and y and then solve for y
y =3x+9
Exchange x and y
x = 3y+9
Then solve for y
Subtract 9 from each side
x-9 =3y+9-9
x-9 = 3y
Divide by 3
1/3(x-9) = 3y/3
1/3(x-9) = y
Distribute
1/3x-3 = y
The inverse is 1/3 x -3