A particle moves on the xy-plane. The y-coordinate of its position is described by the function y(t) = 8t^2 + 10t + 7. And, the x-coordinate of its position is described by the function x(t) = -5(t - 5)^3. Evaluate the first derivative of the y-coordinate with respect to the x-coordinate, dy/dx, at time t = 1.