Need help with this please

Which point lies on a circle with a radius of 5 units and center at p(6, 1)?

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters