0.2X^2Y-0.5XY^2-0.3X^2Y+0.7X^2Y,当x=-1,y=2/3时,最后=?
0.2X^2Y-0.5XY^2-0.3X^2Y+0.7X^2Y,当x=-1,y=2/3时,最后=?
当x=2,y=1时,代数式x^4-xy^3-x^3y-3x^2y+3xy^2+y^4
当x-y=1时,求x^4-xy^3-x^3y-3x^2y+3xy^2+y^4的值
当x=2,y=-1时,求代数式(x+y)(x-y)+(x-y)²-(x²-3xy)的值
当x=2008,y=2009时,求代数式(x-y)/x/(x-(2xy-y^2)/x)
x+y=1,xy=-1/2,求x(x+y)(x-y)-x(x+y)2
当|x-1|+|y+3|=0时,求xy分之一+(x+2)(y+2)分之一+(x+4)(y+4)分之一+(x+6))(y+
已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y
当x=-4 y=-2时 求代数式-3x平方y+3xy平方+x?+3x平方y-3xy平方-y,
当x-y=1,求x^4-xy^3-x^3y-3x^2y+3xy^2+y^4的值
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
当X-Y=2,XY=3时,-3x平方y平方+2y-2x等于?