A curve has equation \(y=(3x-5)^3-2x\).

(i) Find \(\dfrac{dy}{dx}\) and \(\dfrac{d^2y}{dx^2}\).

(ii) Find the exact value of the \(x\)-coordinate of each of the stationary points of the curve.

(iii) Use the second derivative test to determine the nature of each of the stationary points.