The law of cosines is a2+b2-2abcosc=c2 find the value of 2abcosc

An unknown number of kids and buses are getting assigned. when assigning 4 kids to each bus, there are 2 kids that aren't placed in a bus. when assigning 8 kids to each bus, there are 2 empty buses. how many total kids are there?

The perimeter of a movie screen is 54 meters. the screen is 18 meters wide. how tall is it?

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?