Let $$f: R \rightarrow R$$ be a function defined by $$f=\frac{e^{|x|}-e^{-x}}{e^x+e^{-x}}$$ then

Which of the following is not a homogenous function of $$x$$ and $$y$$

If $$2 f\left(x^2\right)+3 f\left(\frac{1}{x^2}\right)=x^2-1, \forall x \in R-\{0\}$$, then $$f\left(x^8\right)$$ is equal to

The range of $$x$$ which satisfy the inequation : $$-5 \leq \frac{2-3 x}{4} \leq 9$$ is