Can u guys me? : ) im having troubles understanding these , !

What's the difference between: x≥0 and nonnegative integer. ?

Danielle earns a 7.25% commission on everything she sells at the electronics store where she works. she also earns a base salary of $750 per week. what were her sales last week if her total earnings for the week were $1,076.25?

The los angels ram scored 26, 30, 48, and 31 pts in their last four games. how many pts do they need to score in super bowl liii in order to have an exact mean average of 35 pts over five games. write and solve and equation. use x to represent the 5th game.