To find an inverse function, first write the function as y = f(x). Then solve that equation for x, because the inverse reverses the original input-output process. Here, Set y=3x+3 and solve for x: x=(y-(3))/3. Replacing y by x gives f^(-1)(x)=(x - (3))/3. So the correct inverse is the expression that isolates the original x after subtracting the constant term and dividing by the coefficient of x.