(x-y)^2-x(x-2y)
3a(a-2)-(a-3)^2
решите плиз

( X - y )^2 - x( X - 2y ) = x^2 - 2xy + y^2 - x^2 + 2xy = y^2 3a( a - 2 ) - ( a - 3 )^2 = 3a^2 - 6a - ( a^2 - 6a + 9 ) = 3a^2 - 6a - a^2 + 6a - 9 = 2a^2 - 9