3.Упростите выраже a) (2x-3y)² + (3x + 2y)² 6) (x + (y-2))²

a) $$(2x-3y)^2 + (3x+2y)^2 = (4x^2 - 12xy + 9y^2) + (9x^2 + 12xy + 4y^2) = 4x^2 - 12xy + 9y^2 + 9x^2 + 12xy + 4y^2 = 13x^2 + 13y^2 = 13(x^2 + y^2)$$.

б) $$ (x + (y-2))^2 = (x + y - 2)^2 = x^2 + y^2 + 4 + 2xy - 4x - 4y = x^2 + y^2 + 2xy - 4x - 4y + 4 $$.

Ответ:

• a) $$ 13(x^2 + y^2) $$
• б) $$ x^2 + y^2 + 2xy - 4x - 4y + 4 $$