- We're asking what the bullet's height is when t = 0; plugging in gives us s = 64 ft.
- The bullet strikes the ground when the height is 0! So we set the height equal to 0, and factor to get t = -1 and t = 4. Since the bullet wasn't shot until t = 0, the answer must be t = 4 seconds.
- This is a parabola, which must reach its height halfway between its two x-intercepts, so at t = (-1+4)/2 = 1.5 seconds.
- We now use the t = 1.5 seconds, and plug it into the formula to s = 100 ft.