Упростите: (x-2y)^2+(2y-x)(x+2y)

( Х - 2у )^2 + ( 2у - Х )( Х + 2у ) = ( Х - 2у )^2 + ( 4у^2 - х^2 ) = х^2 - 4xy + 4y^2 + 4y^2 - x^2 = - 4xy + 8y^2 = - 4( xy - 2y^2 )