{2x^2-xy-y^2-x=3,2x-3y=1,求xyxy就是x.y

（-3x^y+2xy)-( )=4x^+xy x*x+xy=3,xy+y*y=2,则x*x+2xy+y*y=________? (x^3-2x^2+xy^2)/(x-y)+(x+y)(y-x)=? 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 f(xy,x-y)=x^2+3xy+y^2,则f(x,y)=? 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) (-x+2y)(2x+y)-(2x+y)(y-2x)-3xy=?因式分解 x+y=-3 xy+x+y=-2 x/y+y/x=? (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x， （x^2+xy/x-y)/（xy/x-y)计算 -xy^2(x+y)^3+x(x+y)^2因式分解 由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少? (x+3y)/(x^2+xy)-x+y计算题 x-y/xy=( )/x^3y^2 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 已知:x/y=-2,求x^2-2xy-3y^2/x^-6xy 3xy-( )=5xy-2 x-(5x-3y)+( )=-2x+2y 当x-y=2xy时,求4x-3xy-4y/xy