Question

(2x-y)2 - (x+3y)2

2- в квадрате

Answer 1

4x^2 - 4xy + y^2 - (x^2 + 6xy + 9y^2) =
= 4x^2 - 4xy + y^2 - x^2 - 6xy - 9y^2 =
= 3x^2 - 10xy - 8y^2