x*x-xy=-3,2xy-y*y=-8,求2x*x-4xy+y*y的值

|x|/x+y/|y|+xy/|xy|= 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 已知xy/x+y=2,求代数式8x-5xy+8y/-x+3xy-y的值 （-3x^y+2xy)-( )=4x^+xy x*x+xy=3,xy+y*y=2,则x*x+2xy+y*y=________? [-xy^2(2x+y)-8xy)-x^2y)]除以2xy=计算 已知x-xy=8,xy-y=-9,求x+y-2xy的值 当x-y=2xy时,求4x-3xy-4y/xy 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y 由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少? 已知xy/x+y=2,则代数式3x-5y+8y/-x+3xy-y的值 （12x^2y-8xy^2+16xy）/-3x+2y-4=? (12x^2y-8xy^2+16xy）/-3x+2y-4=? f(xy,x-y)=x^2+3xy+y^2,则f(x,y)=? x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值 ( )-(x^2+3xy)=-xy-1/3y^2 ( )*3xy=6x^2y+2xy^2 2xy+5y^2+( )=x^2+3xy