What is the value of 6[4-9.4]

What is the value of 1/3× + 7x, when x =5

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

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)