I need some help. What does it mean when a graph has a double root of something?

What even is a double root?

An arrow is shot vertically upward at a rate of 180ft/s. use the projectile formula h=−16t2+v0t to determine at what time(s), in seconds, the arrow is at a height of 420ft. round your answer(s) to the nearest tenth of a second.

Una caja de galletas contiene 16 paquetes y cada una de estas tiene 12 galletas y se quieren repartir entre 6 niños ¿de cuantas galletas le toca a cada niño?

Quick graph the line for y+2=32(x+4) on the coordinate plane. does anyone know the cordinates will mark brainliest.