®Ò 3 (45) C©u 1: Ph©n tÝch thµnh nh©n tö: a, a 3 + b 3 + c 3 – 3abc b, (x-y) 3 +(y-z) 3 + (z-x) 3 C©u 2: Cho A = 2 2 2 (1 ) 1 x x x − + : 3 3 1 1 ( )( ) 1 1 x x x x x x   − + + −   − +   a, Rót gän A b, T×m A khi x= - 1 2 c, T×m x ®Ó 2A = 1 C©u 3: a, Cho x+y+z = 3. T×m gi¸ trÞ nhá nhÊt cña M = x 2 + y 2 + z 2 b, T×m gi¸ trÞ lín nhÊt cña P = 2 ( 10) x x + C©u 4: a, Cho a,b,c > 0, CMR: 1 < a a b+ + b b c+ + c c a+ < 2 b, Cho x,y ≠ 0 CMR: 2 2 x y + 2 2 y x ≥ x y + y x C©u 5: Cho ABCV ®Òu cã ®é dµi c¹nh lµ a, kÐo dµi BC mét ®o¹n CM =a a, TÝnh sè ®o c¸c gãc ACMV b, CMR: AM ⊥ AB c, KÐo dµi CA ®o¹n AN = a, kÐo dµi AB ®o¹n BP = a. CMR MNPV ®Òu. . ®Ò 3 (45) C©u 1: Ph©n tÝch thµnh nh©n tö: a, a 3 + b 3 + c 3 – 3abc b, (x-y) 3 +(y-z) 3 + (z-x) 3 C©u 2: Cho A = 2 2 2 (1 ) 1 x x x − + : 3 3 1 1 ( )( ) 1 1 x x x x x. x x x   − + + −   − +   a, Rót gän A b, T×m A khi x= - 1 2 c, T×m x ®Ó 2A = 1 C©u 3: a, Cho x+y+z = 3. T×m gi¸ trÞ nhá nhÊt cña M = x 2 + y 2 + z 2 b, T×m gi¸ trÞ lín nhÊt cña P = 2 (