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.)

Answer 1

set equation = 9 and solve. that is write
\[-16t^2+24t+5=9\] or
\[-16t^2+24t-4=0\]

Answer 2

easier if you divide by -4 before solving.
\[4t^2-6t+1=0\]

Answer 3

then use quadratic formula

Answer 4

i get
\[t=\frac{3\pm\sqrt{5}}{4}\]

Answer 5

ignore the - and use a calculator to find
\[\frac{3+\sqrt{5}}{4}\]