
Answer:
Step-by-step explanation:
First part:
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Set h(t) = 73 and solve for t.
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-16t2 + 64t + 16 = 73
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-16t2 + 64t - 57 = 0
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Solve this quadratic equation for t. Â You should get 2 positive solutions. Â The lower value is the time to reach 73 on the way up, and the higher value is the time to reach 73 again, on the way down.
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Second part:
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Set h(t) = 0 and solve the resulting quadratic equation for t. Â You should get a negative solution (which you can discard), and a positive solution. Â The latter is your answer.