If x+y=10 and x-y=4 find the value of x2-y2

Given the following statements, which is the best

The lines shown below are parallel. if the green line has a slope of -1, what is the slope of the red line?

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 =