Simplify into one fraction -4x/x+7 - 8/x+7

Your food costs are $5,500. your total food sales are $11,000. what percent of your food sales do the food costs represent?

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b

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.