Question 369002
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Hi,
position in feet above the ground  =  -16t^2+45t+400
How long will it take for the ball to reach a height of 200 ft. above the ground
200 = -16t^2+45t+400
16t^2 - 45t - 200 = 0
{{{t = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
{{{t = (45 +- sqrt( 14825))/(32) }}}
{{{t = (45 +- 121.8)/(32) }}} Note: solution t < 0 cannot use
t = 166.8 /32 = 5.2 sec