... ( )> 222aabc Þ ( )( )> +-+ - 2aacbabc ÷ ( )> 222bbac Þ ( )( )> +-+ - 2bbcaabc ÷ ( )> 222ccab Þ ( )( )> +-+ - 2cbcaacb Þ ( )( )( )> +-+ - +- 222222abcabcacbbca ... b)2 + (a – c)2 + (b – c)2 ÷ > ; -& gt ; -& gt ;- abc,bac,cab Þ > ;-+ 222ab2bcc , > ;-+ 222ba2acc , > ;-+ 222ca2abb Þ a2 + b2 + c2 < 2(ab + bc + ca). b. abc ³ (a ... 11. Cho a , b ³ 1 , chứng minh: -+ - abab1ba1. ° ( ) ( ) =-+ -= -+ - aa112a1,bb112b1 ° - - ab2ba1,ab2ab1 ° -+ - abab1ba1 12. Cho x, y, z > 1 và x + y + z = 4. C/m: xyz ³ 64(x...