求x^2+xy-y^2和2x^2+xy+3y^的和
已知:x-xy=40,xy-y=-20,求代数式x-y和x+y-2xy的值.
已知(x+y):y=8:3,求2x+5y/3x-y和x^2-xy/y^2+3xy的值
已知XY除于X加Y等于3,求2X-3XY+2Y的和除于-X+3XY-Y的值
x-xy=40,xy-y= -20,求代数式x-y和x+y-2xy
已知x-xy=5,xy-y=-3,求x-y的值 和x+y-2xy的值
已知x^2-xy=60,xy-y^2=40,求代数式x^2-y^2和2x^2-5xy+3y^2的值
已知x^2-xy=8,xy-y^2=3,求代数式x^2-y^2和x^-2xy+y^2的值
xy=-2,x+y=3 求(3xy+10y)+[5x-(2xy+2y-3x)]的运算过程和结果是什么
若x-y=5,xy=6,求x^2-xy^2和x^2y+xy^2
已知xy^2=-2,求-xy(x^2y^5-xy^3-y)的值.
若(y-x)/xy=3,求分式(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.