Câu hỏi 68
Giải phương trình sau với $x,y,z\in\mathbb N$:
$$\left(1+\frac{x}{y+z}\right)^2+\left(1+\frac{y}{z+x}\right)^2+\left(1+\frac{z}{x+y}\right)^2=\frac{27}{4}.$$
$$\left(1+\frac{x}{y+z}\right)^2+\left(1+\frac{y}{z+x}\right)^2+\left(1+\frac{z}{x+y}\right)^2=\frac{27}{4}.$$