3x^2y^2+2xy-7x^2y^2-2分之3xy+2+4x^2y^2其中x=2,y=4分之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-2XY^2+y^3 (-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 x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 化简：x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y) [x(x^2y^2-xy)-y(x^2-x^3y)]/(2x^2y) [x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y [x(x^2y^2-xy)-y(x^2-x^3y)]/3x^2y 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 -xy^2(x+y)^3+x(x+y)^2因式分解 因式分解:8(x-2y)-x(7x+y)+xy. (x+3y)/(x^2+xy)-x+y计算题 -2x(3x-7y)+(x-y)(x^2+xy+y^2） 计算 x*x+xy=3,xy+y*y=2,则x*x+2xy+y*y=________?