1. Giải các pt sau:
a,$x^{2}=y^{2}+\sqrt{y+1}(x, y\in \mathbb{N})$
b, $\sqrt{\frac{1-x}{x}}=\frac{2x+x^{2}}{1+x^{2}}$
c, $x^{4}+2x^{3}+2x^{2}-2x+1=(x^{3}+x)\sqrt{\frac{1-x^{2}}{x}}$.
2.Giải hệ pt:
a,$\left\{\begin{matrix} x\sqrt{x}-8\sqrt{y}=\sqrt{x}+y\sqrt{y}\\ x-y=5 \end{matrix}\right.$
b, $\left\{\begin{matrix} y^{3}=x^{3}+2x^{2}+1\\ xy=z^{2}+2 \end{matrix}\right.(x, y, z\in \mathbb{Z})$
