2x^2+3xy-9y^2-7x+6y+3 因式分解,

化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， 3/x —2/y=3 (2x-3y-xy) / (7xy+9y-6x)= 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 化简求值x-4y/2x-7xy+3y×x-2xy-3y/2x+3xy-2y÷3x-6y/4x-4xy+y,其中：x=1999,y=-1 x^2-xy-6y^2+3xy+y+2 3y/x*x-y*y+x/x*x-2xy+y*y+6y*y/x*x*x-x*x*y-xy*y+y*y*y等于多少? (9x^2y-6xy^2)/3xy 求x^3 - 6x^2y + 11xy^2 - 6y^3 思路x^3 - 6x^2y + 11xy^2 - 6y^3= x^3 - 3x^2y + 2xy^2 - 3x^2y + 9xy^2 - 6y^3= (x^2 - 3xy + 2y^2)(x - 3y)= (x^2 - 2xy - xy + 2y^2)(x - 3y)(x - y)(x - 2y)(x - 3y)求思路 2x-3y/xy×2x^2y^2/6x-9y (X-9y)/(6xy^2-(x+3y)/(9x^2y) 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) 已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y答案是1/x-1/y=2(y-x)/xy=2 得：x-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy)=xy/(-7xy)=-1/7 谁能帮我解释一下=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy) 是怎 9x^2y+y^3-6xy^2因式分解 因式分解6xy^2-9x^2y-y^3 6xy^2-9x^2y-y^3因式分解 x^2y-6xy^2+9y^3