Ihave a simple question if i have (f + g)(x) = 2x + 7 + 6x – 5 and i combine 2x and 6x is it 8x or 8x^2?

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

Wich statement could be used to explain why the function h(x)= x^3 has an inverse relation that is also a function

Which expression gives the exact value of x?