Is the line through points p(0, –9) and q(2, –8) perpendicular to the line through points r(1, 4) and s(3, 3)? explain.

yes; their slopes are equal.
yes; their slopes have product –1.
no; their slopes are not reciprocals.
yes; their slopes have product –1.

Which is the equation of an ellipse with directrices at x = ±4 and foci at (2, 0) and (−2, 0)?

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 =

How do you find the circumfrance of a circle?