Question

Use the quadratic formula to solve the problem.

A soccer player throws the ball onto the field from the sideline. An equation modeling the ball's flight is h = -16t2 + 18t + 2. In how many seconds will the ball reach the ground?
A. in about 2 seconds
B. in about 1.2 seconds
C. in about 1.8 seconds
D. Cannot be determined

Answer 1

solve
\[-16t^2+18t+2=0\] to simplify your calculation, divide by -2 and start with
\[8t^2-9t-1=0\] then use
\[t=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\] with
\[a=8,b=-9,c=-1\] to get
\[t=\frac{9+\sqrt{113}}{16}\] ignore the negative answer and then whip out a calculator