Aball is thrown from an initial height of 7 feet with an initial upward velocity of 28/fts . the ball's height h (in feet) after t seconds is given by the following. =h+7−28t16t2 find all values of t for which the ball's height is 15 feet. round your answer(s) to the nearest hundredth. (if there is more than one answer, use the "or" button.)