Giải các phương trình sau:
1) \(\frac{1}{\sqrt{x}}+\frac{1}{\sqrt{x}+1}=\sqrt{5}.\left(\frac{1}{\sqrt{6x-1}}+\frac{1}{\sqrt{9x-4}}\right).\)
2) \(\frac{1}{\sqrt{3}x}+\frac{1}{\sqrt{9x-3}}=\frac{1}{\sqrt{5x-1}}+\frac{1}{\sqrt{7x-2}}\)
3) \(\hept{\begin{cases}x^3-y^3-z^3=3xyz\\x^3=2\left(y+z\right)\end{cases}}\)
4) \(\hept{\begin{cases}x^3+y^3+2xyz=z^3\\z^3=\left(2x+2y\right)^3\end{cases}}\)