At the start of the basketball game, the referee tosses a ball for a jump ball. The equation that models the height of the ball is
h(t) = -16t2 + 24t + 5
During what time interval is the height of the ball above 9 feet? (Round your answer to the nearest tenth of a second.)
a) .4 seconds to 1.9 seconds
b) .2 seconds to 1.3 seconds
c) .6 seconds to 1.8 seconds
d) .5 seconds to 2.1 seconds

Question

At the start of the basketball game, the referee tosses a ball for a jump ball. The equation that models the height of the ball is 
h(t) = -16t2 + 24t + 5
During what time interval is the height of the ball above 9 feet? (Round your answer to the nearest tenth of a second.)
	a)	.4 seconds to 1.9 seconds
	b)	.2 seconds to 1.3 seconds
	c)	.6 seconds to 1.8 seconds
	d)	.5 seconds to 2.1 seconds

anonymous · Answer

you'll need to solve the equation:  $\huge 9=-16t^2+24t+5 $
use the quadratic formula for this...
$$\huge x=\frac{-b\pm \sqrt{b^2-4ac}}{2a} $$