A In Problems 9-14, assume that x = x(t) and y = y(t) . Find the indicated rate, given the other information. 9. y = x2 + 2; dx/dt = 3 when x = 5; find dy /dt 10. y = x' - 3; dx /dt = -2 when x = 2; find dy / dt 11. x2 + y' = 1; dy / dt = -4 when x = -0.6 and y = 0.8; find dx / dt 12. x2 + y2 = 4; dy/ dt = 5 when x = 1.2 and y = -1.6; find dx / dt 13. x- + 3xy + y' = 11; dx /dt = 2 when x = 1 and y = 2; find dy / dt