... BunhiacôpSki0 ,25 0 ,25 SNDAMBC0 ,25 0 ,25 0 ,25 0,50 ,25 1,5Lại có: ( ) 2 2 2 0 2 2 2 10ya by−⇒ + ≥+Nhng 2 1 2 240 0 2 0y xx ÷ ÷ ÷ = + ≥§Æt: 2 4 , 00y t t= + ≥( ) 2 29 2 215 54 9 9 4 5 16 2 25 5 5 5 5 25 ta ... 1 2 2 2 0 0 0 0 2 00x y y xxx+ = = +Vậy (3) 2 2 00 0y ay b + + = 2 2 2 2 2 2( 2) ( ) ( )( 1)0 0 0y ay b a b y = + + + theo BunhiacôpSki0 ,25 0 ,25 SNDAMBC0 ,25 0 ,25 0 ,25 0,50 ,25 1,5Lại ... 20 *8 20 05 21 65(1) 20 *8 20 05 21 65 (2) x yy x− + + =− + + =§/K: , 160x y≥LÊy (1)- (2) ta cã: 20 *8 20 05 20 05 20 *8x y x y− + + = + + −( ) ( ) 2 ( 20 *8)( 20 05) 2 ( 20 05)( 20 *8)x y...