Question 262788: a diver jumps from a diving board 24' above a pool. After t seconds, the diver's height h above the water (in feet) is given by the expression -16t^2+8t+24 in how many seconds will the diver hit the water (h=0)
that is how it is in the book and i am lost
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! a diver jumps from a diving board 24' above a pool.
After t seconds, the diver's height h above the water (in feet) is given by the expression -16t^2+8t+24
in how many seconds will the diver hit the water (h=0)
:
The water is h=0, so the equation will be:
-16t^2 + 8t + 24 = 0
:
Simplify and change the signs, divide by -8; results:
2t^2 - t - 3 = 0
:
Factor
(2t-3)(t+1) = 0
:
Positive solution is what we want here
2t = +3
t = 1.5 sec to hit water
;
:
See if that is true, replace t with 1.5 in the original equation
h = -16(1.5^2) + 8(1.5) + 24
h = -16(2.25) + 12 + 24
h = -36 + 36
h = 0; confirms our value for t=1.5
:
Has this helped you find your way? Not that hard, right?
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