bài 1 : rút gọn
A = ( 2x + 1)2 + 2( 4x2 - 1) + ( 2x - 1 )2
B = x( x - 4 )(x+ 4 ) -( x2 + 1)(x2 - 1)
C = ( x2 - 1 ) ( x - 3 ) - ( x - 3 )( x2 + 3x + 9 )
bài 2 : phân tích
a, x2 + 4y2 - 2x +4xy - 4y
b, ( x + 2 )( x + 3 )( x+ 4 )( x+ 5 ) - 24
tks trc nha ! _ove