Find the equation of this line

Write numerical coefficient of y² in the expression 2x² - 15xy – 7y²

Aball is thrown from a height of 139 feet with an initial downward velocity of 15 ft/s. the ball's height h (in feet) after t seconds is given by the following. h=139-15t-16t^2 how long after the ball is thrown does it hit the ground? round your answer(s) to the nearest hundredth. (if there is more than one answer, use the "or" button.) t =

An arc subtends a central angle measuring 7pi/4 radians what fraction of the circumference is this arc?