1-2xy-x^2-y^2
已知:x-y=1,xy=-2,求(3x-4y+2xy)-(2x-5y+5xy)的值
已知:x-y=1,xy=-2,求(3x-4y 2xy)-(2x-5y 5xy)的值
3y/2x+2y+2xy/x²+xy 2x/x²-64y²-1/x-8y (1/a+1/b
1-2xy-x^2-y^2
xy-xy分之2xy-y和x-4分之4-4x+x求化简
(x+y-2xy)(x+y-2)+(1-xy)²
x²-2xy+y²-2x+2y+1
已知x²-xy=4,y²-xy=9求下面代数式的值(1)x²-2xy+y²;(2
已知1/x-1/y=4,求(2x+xy-2y)/(x-2xy-y)的值
已知x=3 y=1\3,求3x²y-[2xy²-2﹙xy-3\2x²y﹚+xy]+3xy&
化简.x^2-3xy/x^2-6xy+9y^2
已知1÷y-1÷x=5,求(2x+4xy-2y)÷(x-3xy-y)的值