Answer:
(a) 4 seconds
Step-by-step explanation:
The given point (4, 0) on the parabola tells you the answer to the question: the coin was in the air 4 seconds before its height is 0. It is no longer in the air at that point.
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<em>Additional comment</em>
In order to match the rest of the problem statement, the first given x-intercept must be (-2, 0).
