The correct answer of the given question above would be y= 1/3x-3. The inverse of the given expression is y= 1/3x-3. When getting the inverse of an expression, just replace x by y and y by x then solve for y. Based on the given function above, you have x= 3y + 9 and then to 3y =x-9 which will give you the result y = (x -9)/3 or y = 1/3x -3. Hope that helps!