If $LaTeX: \displaystyle f(x)=x^{2} + 6 x - 2$ 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 $LaTeX: \displaystyle (f\circ g)(x)=f(g(x))=6 \sqrt{x} + x - 2$ .