\ \ - XOay NAM HOC 2010-20ll TRTIONG THPT r,A On rHr CnUyfN DE LOp rr r,AN y6n: Torln- ruiii O hoi gian: 180'(khdng Ciu I Cho b6t phucng trinh: J *2 - J " Ciai b6t phuong trinh vcri m:-2 I , r* -rr[;J kC thcri gian giao 0: abc = l Chring minh rdng: lll a+b+l - b-+c+l -.;;= ' N6i du Gi6i bdt phucrng trinh Ei6u kiQn: t = J a a2 - -r > vli m:-2 z J -zUatphucrng t'-t+m