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A ball is thrown in air and it's height, h(t)

in feet, at any time, t
in seconds, is represented by the equation h(t)=−t2+7t
. When is the ball higher than 10 feet off the ground?

1 Answer

2 votes

Explanation:

To determine when the ball is higher than 10 feet off the ground, we need to find the values of t for which h(t) is greater than 10.Given the equation h(t) = -t^2 + 7t, we can set up the inequality:

t^2 + 7t > 10

Rearranging the inequality, we have:

t^2 + 7t - 10 > 0

To solve this quadratic inequality, we can factorize it or use the quadratic formula. Let's factorize it:

(t - 2)(t + 5) > 0

Now we have two factors: (t - 2) and (t + 5).

To determine when the inequality is true, we consider the signs of each factor.

When (t - 2) > 0 and (t + 5) > 0, both factors are positive. This occurs when t > 2.When (t - 2) < 0 and (t + 5) < 0, both factors are negative. This occurs when t < -5.

Therefore, the ball is higher than 10 feet off the ground when t < -5 or t > 2.In the context of time, it means the ball is higher than 10 feet before it is thrown (t < -5) or after approximately 2 seconds (t > 2).

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