已知x^2-xy=8,xy-y^2=3,分别求下列各式的值：(1)x^2-y^2 (2)x^2-2xy+y^2

已知xy/x+y=2,求代数式8x-5xy+8y/-x+3xy-y的值 已知x-xy=8,xy-y=-9,求x+y-2xy的值 由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少? 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^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2 已知2x+xy=10,3y+2xy=6.求4x+8xy+9y=? 已知x^+xy=-5,xy+y^=8,求2x^-xy-3y^的值都是2次 已知x:y=3:2,求(x²+3xy)/(xy+2xy) 已知xy为正整数,3xy=2x+3y+5.求xy=? 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+xy+y=3,则(3x+2xy+3y)/(2x+xy+2y)= 已知x-y=3xy,则2x+3xy-2y除以x-2xy-y=? 已知x-y=3xy,则2x+3xy-2y/x-2xy-y= 已知y=3xy+x,求代数式2x+3xy-2y/x-2xy-y的值 已知x-y/xy=3,求分式2x+3xy-2y/x-2xy-y的值. 已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y)