Consider a thin lens whose left-hand surface is concave and spherical with radius of curvature R, while its right-hand s

[answerhappygod]

Consider a thin lens whose left-hand surface is concave and
spherical with radius of curvature R, while its right-hand surface
is flat. An object is located 12.0cm to the left of the center of
the lens, while its image is 8.0 cm to the left of the center of
the lens. Calculate R. Assume that the lens is made of glass with
refractive index 1.50