... 1 1 4( 2005 )x x x khốiD+ + + + = 8, 2 1 2 1 2( 2000 )x x x x BCVT+ = 9, 3(2 2) 2 6( 01)x x x HVKTQS+ = + + 10, 2 2 2 8 6 1 2 2( 2000 )x x x x BK+ + + = + 11, 2 2 2 2 5 5 1 1 1( 2001 ) ... = − + = 2 2 3 2 ( 2001 ) 3 2 x y x TL y x y 20, + + − = − + + − = 5 2 7 ( 1 2000 ) 5 2 7 x y NN y x 21, + = − + = 2 2 2 2 2 3 ( 2003 ) 2 3 y y x KhèiB x x y 22, ... 19 ( 2001 ) 6 x y x TM y xy x 24, − + = − − + = 2 2 2 2 2 3 9 ( ) 2 13 15 0 x xy y HVNH TPHCM x xy y 25, − = − + = 2 2 2 2 2 ( ) 3 ( § 97) ( ) 10 y x y x M C x x y y Bài tập...