If $LaTeX: \displaystyle f(x)=\frac{2 x - 4}{- 4 x^{2} - 9 x + 5}$ and $LaTeX: \displaystyle g(x)=\sqrt{x}$ find $LaTeX: \displaystyle (f\circ g)(x)$ .

Evaluating $LaTeX: \displaystyle f(x)$ at $LaTeX: \displaystyle g(x)$ gives $LaTeX: \displaystyle (f\circ g)(x)=f(g(x))=\frac{2 \sqrt{x} - 4}{- 9 \sqrt{x} - 4 x + 5}$ .