Đặt [tex]\left\{\begin{matrix} u=\sqrt{x+2}\\ v=\sqrt{y+2} \end{matrix}\right.\Rightarrow \left\{\begin{matrix} u^2-v=\frac{7}{2}\\ v^2+2(u^2-4)u=\frac{1}{4} \end{matrix}\right.\Rightarrow \left\{\begin{matrix} v=u^2-\frac{7}{2}\\ (u^2-\frac{7}{2})^2+2u^3-8u-\frac{1}{4}=0 \end{matrix}\right.\Rightarrow \left\{\begin{matrix} v=u^2-\frac{7}{2}\\ (u-1)(u-2)(u+2)(u+3)=0 \end{matrix}\right.[/tex]
Sau đó thế lại.