The domain of the function $$f(x)=\frac{1}{\sqrt{x+|x|}}$$ is

The approximate value of the function $$f(x)=x^3-3 x+5$$ at $$x=1.99$$ is

If $$f(x)=\frac{2 x+3}{3 x-2}, x \neq \frac{2}{3}$$, then the function $$f$$ of is