6=a/4+6 I need the answer for math please

What expression is equivalent to (2x-1)(x-3)?

What is the sum of the first 8 terms of the geometric series

Sara goes on a slingshot ride in an amusement park. she is strapped into a spherical ball that has a radius 3*10^2 of centimeters. what is the volume of air in the spherical ball? use this formula: volume of a sphere=4/3pi, r^3 , where r is the sphere’s radius.