Hey,

I haven't fully reviewed your method yet, but it looks like you've made a cancelling error between the last two stages. With:

, you can't cancel an x because not everything in the numerator has an x to be cancelled.

If it was:

, you could cancel the x because this would equal:

, but in the original question, this is not the case.

Anyway, here's how I would solve it:

Times both sides by :

Times both sides by :

Can you finish from there?