1 câu trả lời
Bài làm
4x^2 + 4x - 4xy + y^2 - 2y + 5
= ( 4x^2 - 4xy + y^2 ) + ( 4x - 2y ) + 5
= [ ( 2x )^2 - 2 . 2x . y + y^2 ] + 5
= ( 2x - y ) ^2 + ( 4x - 2y ) + 5
= ( 2x - y ) ^2 + 2( 2x - y ) + 5
= ( 2x - y )( 2x - y + 2 ) + 5
= 1( 2x - y )( 2x - y + 2 ) + 5 . 1
= 1[ ( 2x - y )( 2x - y + 2 ) + 5 ]
# Học tốt #