How to silve distance and midpoint of pralalla & perpendicular lines

It says factor each expression 49x-28?

Consider a cube that has sides of length l. now consider putting the largest sphere you can inside this cube without any point on the sphere lying outside of the cube. the volume ratio -volume of the sphere/ volume of the cube is 1. 5.2 × 10−1 2. 3.8 × 10−1 3. 1.9 4. 2.5 × 10−1 5. 3.8

Which equation expression the relationship between the number of boxes b and the number of cans c and the proportion is 48