A particle is moving along the curve y = x + x in such a way that the y-coordinate is increasing at a rate of 1/2 units per second. At what rate is the x-coordinate changing at the instant x = 2? A. 1/8 units/sec B. 1/10 units/sec C. 1/ uonits/sec D. 1/4 units/sec E. 1/12 units/sec F. None of these. An point moves along the curve y = 4x2 + 1 in such a way tha the y-value is decreasing at the rate of 2 units per second. At what rate is x changing when x = 5? A. -1/10 units/sec B. -1/12 units/sec C. -1/4 units/sec D. -1/5 units/sec E. -1/20 units/sec F. None of these