Question 431119
{{{ d= -16t^2 - 4t + 432 }}}
{{{ 300 = -16t^2 -4t + 432 }}}
{{{ -16t^2 - 4t = - 132 }}}
{{{ 16t^2 + 4t - 132 = 0 }}} 
{{{  4t^2 + t - 33 = 0 }}}
{{{ t = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}  
{{{ a = 4 }}}
{{{ b = 1 }}}
{{{ c = -33 }}}
{{{ t = (-1 +- sqrt( 1^2-4*4*(-33) ))/(2*4) }}}  
{{{ t = (-1 +- sqrt( 1  + 528 )) / 8 }}} 
{{{ t = (-1 +- 23) / 8 }}} 
{{{ t = -3 }}} (can't use this)
{{{ t = 11/4 }}}
The rock is 300 ft from the ground
when t = 2.75 sec