Simplify $\displaystyle y = [-\frac{2(\sqrt{x}-2)^2(x-1)}{\sqrt{x}-4}] - 1$
Yes, it was probably just a latex typo.
And Punch:
If you want, you could do that and expand the brackets on the numerator. You will find that a few terms (like the $\displaystyle x^1$ terms) will cancel and you can play around with the indices (the square roots that pop up).