计算：(x^2y+xy^2)/(x+y)；(4a^2-12ab+9b^2)/(3b-2a)；(4x^2-6x^2y)/(2-3y)；[(x+3y)^2-4x^2]/(x+y).要有计算过程

计算：(x^2y+xy^2)/(x+y)；(4a^2-12ab+9b^2)/(3b-2a)；(4x^2-6x^2y)/(2-3y)；[(x+3y)^2-4x^2]/(x+y).
要有计算过程

xy；-2a+3b；2x^2y；-3x+9