ta co x+y+3/z=y+z+1/x=x+z+2/y=1/x+y+z, theo tinh chat cua day ti so bang nhau ta co
x+y+3/z=y+z+1/x=x+z+2/y=1/x+y+z=(3+1+2)+2x+2y+2z/z+y+x=6+2(x+y+z)/x+y+z=8
suy ra 1/x+y+z=8 suy ra x+y+z=1/8(1)
ta co x+y+3/z=y+z+1/x=x+z+2/y=8
suy ra x+y+3/z+1=y+z+1/x=x+z+2/y+1
suy ra x+y+z+3/z=y+z+x+1=x+z+y+2/y=9(2)
the (1) vao (2) ta co
1/8+3/z=1/8+1/y=1/8+2/x
suy ra 25/8/z=9/8/y=17/8/x
suy ra z=25/8:8=25/64
y=9/8:8=9/64
x=17/8:8=17/64
nho nhe