g A plano-convex lens creates a lateral magnification of three for an object 10 cm away. If the convex curvature is given by R = 9 cm, what is the index of refraction of the material used to construct the lens?

The answer is frictional force

What formula  this one  (x_/

The purpose of a lab is to do your "expirements" the importance of the topic is so you can now what the story is about and the last one is because no one is me with my question ( what is 3 over 4 x - 9 = 27 maybe you can )