3x^2+5xy-2y^2+x+9y-4怎么化简

5xy^2-[3xy^2-(4xy^2-2x^y)]+x^2y-xy^2如何化简 (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y) 化简求值:根号x^-2xy+y^2 + x^2 -6xy+9y^2/x-3y,其中x=根号3,y=根号5 (x^2-xy)y÷y-x/xy怎么做? x*-2xy+3y*=9 4x*-5xy+6y*=30 [-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y- 化简求值3x-2y-5xy-（2x-3y+2xy）,其中x+y=4,xy=-7 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) 化简分式方程:x*x-xy-y*y/x*x-3x-6y+2xy 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) x^8-x^7y+x^6y^2-x^5y^3+x^4y^4-x^3y^5+x^2y^-xy^7+y^8