已知2y-2x=-2010,xy=10,求2x的四次方y的三次方-x的三次方y的四次方错了是已知y-2x=-2010,xy=10,求2x的四次方y的三次方-x的三次方y的四次方

已知x-xy=10,xy-y=2,则x-y=（ ）,-2xy+x+y=（ ）. 已知x-xy=20,xy-y=-10,则x-y=( ),x+y-2xy=( ). 已知x-xy=20,xy-y=-10,则x-y=?,x+y-2xy? 已知x+y=1,xy=-2,则x²y+xy²-2xy 已知x-xy=8,xy-y=-9,求x+y-2xy的值 已知2x+xy=10,3y+2xy=6.求4x+8xy+9y=? 由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少? 已知x+y=-2,求代数式(6xy+10y)+[4x-2(3xy+2y-x)] 已知x+y=3,xy=-10,求（1）x平方-xy+y平方；（2）|x-y| 已知:x>0,y>0,且x- 10√xy+25y=0,求2x+√xy+3y/x+√xy-y 已知X+y=6,xy=7 求x^2y+xy^2=已知X+y=6,xy=7 x^2y+xy^2 已知xy^2=-2,求-xy（x^2y^5-xy^3-y)的值. 已知xy^2=-2 求-xy(x^2y^5-xy^3-y) 已知xy^2=-2xy(x^2y^5-xy^3-y) 已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理.已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理. 已知x^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2 已知x-y=3xy,则2x+3xy-2y除以x-2xy-y=? 已知x+xy+y=3,则(3x+2xy+3y)/(2x+xy+2y)=