4. A 25-foot ladder is leaning against a house (see figure). If the base of the ladder is pulled away from the house at a rate of 2 feet per second, the top will move down the wall at a fu/sec where x is the distance between the base of the ladder and 2x rate of r = V625-x2 the house. Find the rate r when x is 7 feet. 25 ft se 48 A) fu/sec 7 B) r= ft/sec 24 12 C) r= ft/sec 7 24 D) r= ft/sec 7 7 E) ft/sec 12 x2 - 49 5. Find the vertical asymptotes (if any) of the function f (x) =- x2 + 4x-21 A) x =3 B) x = 7 C) x =-3 D) x = 21 E) x =-7