math HELP
posted by Coach on .
When a ball is thrown in the air, the height h of a ball in feet t seconds after the ball is thrown in the air, is given by the equation height = 25t–16t²
Use the quadratic equation to determine how many seconds goes by before the ball hits the ground?

When the ball hits the ground height be zero.
25 t  16 t ^ 2 = 0
t ( 25  16 t ) = 0
This equation will be zero when t = 0
OR
25  16 t = 0
25  16 t = 0 Add 16 to both sides
25  16 t + 16 t = 0 + 16 t
25 = 16 t Divide both sides by 16
25 / 16 = t
t = 25 / 16
When t = 0 ball does not fly.
So solution are :
t = 25 / 16 seconds