Differentiation - Tangents and Normals at a Point

Assume the same two integration constants are used in the resulting formula on both intervals \(x<2\) and \(x>2\).

At any point \((x, y)\) on a curve, \(\frac{\mathrm{d}^2y}{\mathrm{d}x^2} = \frac{18}{(x-2)^3}\). The gradient of the curve at \((5, 20)\) is \(2\).

Find the equation of the tangent to the curve when it cuts the \(y\)-axis.