6x^2+xy-2y^2+2x-8y-8和x^3-3x^2-13x+15以及（y+1)^4+（y+3)^4-272还有x^4 +x^2y^2+y^4分解因式具体过程!

因式分解:8(x-2y)-x(7x+y)+xy. 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] [ 2x-6y][8-9xy]÷xy等于? xy-2x+6y-12 xy+8 因式分解 (x^2)y-6xy+8y 3(x-y)²-7(x-y)+8(x-y)²+6(x-y)求详细过程（2） 5xy-4x²y-8xy²+3xy-xy²+4x²y (8X^3Y-6X^2Y^2-2XY^3)/(3XY) (8X^3Y-6X^2Y^2-2XY^3)/(3XY) (-2x²y+6x³y⁴-8xy)÷(-2xy) 因式分解 6x(x-y)^2-8y(y-x)^33x-4xy+4y^2 [-xy^2(2x+y)-8xy)-x^2y)]除以2xy=计算 (-x-y)(x^2+xy+y^2) 已知x-xy=8,xy-y=-9,求x+y-2xy的值 化简x^-y^/x^-2xy+y^ 2*(x-y)²(y-x)(xy) 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