Question

[Hoàng Nguyên Hiệp]

Cho xyz=1. Chứng minh: x/(xy+x+1)+y/(yz+y+1)+z/(xz+z+1)

Answer 1

[Lê Anh Tú]

(x/ 1+x+xy)+ (y/ 1+y+yz) + ( z/ 1+z+zx) 

\(=\frac{1}{\left(yz+1+y\right)}+\frac{y}{\left(1+y+yz\right)}+\frac{yz}{\left(y+yz+xyz\right)}\)
\(=\frac{1}{\left(yz+1+y\right)}+\frac{y}{\left(1+y+yz\right)}+\frac{yz}{\left(y+yz+1\right)}\)
\(=\frac{\left(1+y+yz\right)}{\left(y+yz+1\right)}=1\)

Vậy (x/ 1+x+xy)+ (y/ 1+y+yz) + ( z/ 1+z+zx)=1(Đpcm)

Answer 2

[Pain Địa Ngục Đạo]

chứng minh VT làm sao ? đề thiếu ?