Transformations of functions problem 5

The diagram shows the curve with equation and the tangent to the curve at the point P. The point P has x-coordinate 3. The graph of is transformed by a stretch of scale factor in the x-direction. The point Q is the image of P under this transformation. The transformed shaded region is bounded by the transformed curve, the x-axis and the tangent to the transformed curve at Q. Find the equation of the transformed curve in the form , where and are integers to be found.