Recovering a function after successive graph transformations

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

1. A translation by \(2\) 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 \(5\) units in the positive \(y\)-direction.

The equation of the resulting curve is \(y=12-\dfrac{4}{3}x+e^{\frac{2}{3}x-4}\).

Find the equation of the original curve \(y=f(x)\).[5]