What is the difference between nomads and hunter-gathers of ancient times?

After t seconds, a ball tossed in the air from the ground level reaches a height of h feet given by the equation h = 144t-16t^2. after how many seconds will the ball hit the ground before rebounding?

Identify the number 127 as a rational or irrational. explain

Cd is the perpendicular bisector of both xy and st, and cy=20. find xy.