数学题(x+y+3)(x^2+y^2+2xy-3x-3y+9)

数学题(x+y+3)(x^2+y^2+2xy-3x-3y+9) 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) [x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y (x+y)(x-y)-(2xy+3y)平方 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy) 9xy(x-y)(x+1)-3y(x-y)(3x+2y)+6y的平方(x-y)(x+1),因式分解 (3xy)平方/(-xy)+(x-2y)平方-(x+2y)(x-2y)＝ 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y