(14x^3*y-7x^2*y^2+21xy^3)/(-7xy)
x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2
1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y)
xy=-2,x+y=3,求代数式(4xy+12y)+[7x-(3xy+4y-x)]
(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)
已知x=3y,试求(x-y)^2+2xy-y^2/x^2+7xy+y^2
已知xy^2=-2求xy(2x^3y^7+5x^2y
xy/3x+2y=1/8 xy/2x+3y=1/7
计算:(-7x²y)(2x²y-3xy³+xy)
已知x+y=4,xy=2,求代数式2(3x+2xy)+(2xy+3x+2y)-(4xy-7y)的值
x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值
x^2-xy-6y^2+3xy+y+2
已知X/Y=2/7,求x^2-3XY+2Y^2/X^2-2XY+Y^2