Please help me with this questions.

3.) An object 10 mm tall is placed 12 cm in front of a convex spherical mirror whose radius of curvature is 20 cm. (a.) Determine the position, size and orientation of the image. (b.) Draw the corresponding ray diagram. (c.) Repeat parts (a.) and (b.) if the convex mirror is replaced by a concave one. 4.) An object is placed 30 cm in front of a lens. An upright image is created three times smaller than the object. (a.) Calculate the focal length of the lens. Is it converging or diverging? (b. ) Draw the corresponding ray diagram. (c.) Repeat parts (a.) and (b.) if the image is inverted and three times smaller than the object. 5.) Two slits spaced 0.130 mm apart are placed 90 cm from a screen and illuminated by coherent light of wavelength 550 . (a.) What is the distance in millimeters on the screen between the center of the central maximum and the center of the third-order maximum? (b.) What is the distance in millimeters on the screen between the center of the central maximum and the first dark fringe