SOLUTION: josefina hit a tennis ball into the air with an initial upward velocity of 16 feet per second. The height, h in feet of the ball above the ground can be modeled by h=-16t^2+16t+3,

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: josefina hit a tennis ball into the air with an initial upward velocity of 16 feet per second. The height, h in feet of the ball above the ground can be modeled by h=-16t^2+16t+3,      Log On


   



Question 84295: josefina hit a tennis ball into the air with an initial upward velocity of 16 feet per second. The height, h in feet of the ball above the ground can be modeled by h=-16t^2+16t+3, where t is the time in seconds after josefina hit the tennis ball. Find the time it takes the ball to reach 7 feet above the ground.

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Answer by vertciel(183) About Me  (Show Source):
You can put this solution on YOUR website!
h= -16t^2 + 16t + 3
You want to find t, but you know the height (7 feet) so just substitute that in.
7 = -16t^2 + 16t + 3
-16t^2 + 16t + 3 = 7 <-- Rewrote it to make it look nicer.
-16t^2 + 16t - 4 = 0
This is a quadratic equation. Try to solve it yourself but if you need more help, please write back.