-2x^3y+2x^2y^2-1/2xy^3a^2-8ab+16b^2-c^2-2c-1

1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) .(x+y-2)(x+y-2xy)+(xy-1)^2 因式分解x^2y^2+x^2y+xy^2+3xy+x+y+1 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y (x+y)(x+y+2xy)+(xy+1)(xy-1)(x+y)(x-y)+4(y-1) 计算3xy[2xy-x(y-2)+x-1] X^Y-2XY^2+y^3 x²/xy-x/y 3x/4x+y - x-2y/4x+y (1-y/y+x)÷x/y²-x² (-x-y)(x^2+xy+y^2) 化简x^-y^/x^-2xy+y^ 2*(x-y)²(y-x)(xy) （x^2+xy/x-y)/（xy/x-y)计算 x²-y²+5x+3y+4（x+y-2xy)(x+y-z)+(xy-1）² (-1/3xy)^2•[xy(2x-y)-2x(xy-y^2)] xy(xy+1)+xy+3-2(x+y+1/2)-(x+y-1)^2因式分解 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) (-3分之1xy)的平方×[xy(2x-y)-2x(xy-y的平方)]