A screen is placed a distance d = 42.0 cm to the right of a small object. At what two distances to the right of the object can a converging lens of focal length +7.00 cmbe placed if the real image of the object is at the location of the screen?

(Hint: Use the thin lens equation in the form s' = sf s - f , so s'(s - f) = sf. Write s' = d - s and solve for s in the resulting quadratic equation.) I know the distances are 8.875 and 33.124 but i do no not what the smallest value of d can be to have the image formed on the screen.