Recovering a logarithmic function after graph transformations

A curve, \(y=f(x)\), undergoes the transformations \(A\), \(B\), \(C\) and \(D\) in succession:

1. A translation by \(5\) units in the negative \(x\)-direction.
2. A scaling by a scale factor of \(3\) parallel to the \(x\)-axis.
3. A reflection about the \(y\)-axis.
4. A translation by \(2\) units in the negative \(y\)-direction.

The equation of the resulting curve is \(y=9-x+2\ln\left(5-\dfrac{x}{3}\right)\), where \(x<15\).

Find the equation of the original curve \(y=f(x)\), and state its domain.[6]