13.x^2-12xy+36y^2-6x+36y+8 用分组分解法来分解

因式分解：x^2 -12xy+36y^2 - x + 6y （x-6y)(x-6y-1) 12X^2+XY-6Y^2 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) xy-2x+6y-12 xy+8 (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 解方程组：xy/x+y=-6(1) 2xy/x+2y=12(2) 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) （x^2+xy/x-y)/（xy/x-y)计算 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) x^2-xy-6y^2+3xy+y+2 x^2+xy+x=36,y^2+xy+y=20,求x+y. 3xy(x^2y-xy^2+xy)-xy^2(2x^2-6xy+2x)过程 xy-2{xy-[3x^2y-(4xy^2+0.5xy)]+4x^2y}+6xy^2 （X-3xy+4xy-y）-[-2x-2（xy-3/2xy）-y]+6xy的过程 因式分解：-3x^3+6x^2y-3xy^21.-3x^3+6x^2y-3xy^22.4a^2+4a+13.(x^2-3)^2-12(x^2-3)+36 (-4x(2xy+3xy^2)+12(x^2y)^2y^3)÷（-6xy） (-x-y)(x^2+xy+y^2)