Giải thích các bước giải :
`x/(y+z)+y/(z+x)+z/(x+y)=1`
`<=>(x+y+z)(x/(y+z)+y/(z+x)+z/(x+y))=x+y+z`
`<=>(x(x+y+z))/(y+z)+(y(x+y+z))/(z+x)+(z(x+y+z))/(x+y)=x+y+z`
`<=>(x^2+x(y+z))/(y+z)+(y^2+y(z+x))/(z+x)+(z^2+z(x+y))/(x+y)=x+y+z`
`<=>x^2/(y+z)+(x(y+z))/(y+z)+y^2/(z+x)+(y(z+x))/(z+x)+z^2/(x+y)+(z(x+y))/(x+y)=x+y+z`
`<=>x^2/(y+z)+x+y^2/(z+x)+y+z^2/(x+y)+z=x+y+z`
`<=>x^2/(y+z)+y^2/(z+x)+z^2/(x+y)=x+y+z-x-y-z`
`<=>x^2/(y+z)+y^2/(z+x)+z^2/(x+y)=0`
Vậy ....
~Chúc bạn học tốt !!!~
