1) $\frac{2x^5+3x^4-14x^3}{\sqrt{x+2}}=(4x^4+14x^3+3x^2+2)(1-\frac{2}{\sqrt{x+2}})$2) $\begin{cases}x^2+\frac{x}{x+1}=(y+2)\sqrt{(x+1)(y+1)} \\ 3x^2-8x-3=4(x+1)\sqrt{y+1} \end{cases}$
3) $\begin{cases}2y^3+y+2x\sqrt{1-x}=3\sqrt{1-x} \\ \sqrt{9-4y}=2x^2+6y^2-7 \end{cases}$