help với
cho x,y,z>0 thỏa mãn: x+y+z=3" role="presentation" style="font-size: 13.696px; display: inline; line-height: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">x+y+z=3x+y+z=3. c/m: xx+3x+yz+yy+3y+xz+zz+3z+yx≤1" role="presentation" style="font-size: 13.696px; display: inline-table; line-height: normal; word-spacing: normal; word-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">xx+3x+yz−−−−−−√+yy+3y+xz−−−−−−√+zz+3z+yx−−−−−−√≤1