R
rooney_10


cho (x+y+z)(1/x+1/y+1/z)=11 tim max (x^2+y^2+z^2)(1/x^2+1/y^2+1/z^2)
bai nay tuan truoc la bai cuoi thi thu DHQG ko co dieu kien dau bang kho wa
bai nay tuan truoc la bai cuoi thi thu DHQG ko co dieu kien dau bang kho wa