已知x²-4x+y²-2y+5=0则xy=
已知x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy
已知x²-4x+y²-2y+5=0则xy=
已知实数x,y满足5x²+2y²+1=6xy+4x-2y,则x²-xy+2000y
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知X²+Y²+X²Y²-4XY+1=0 求:(X-Y)^2008-(XY)^2
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知x²-3xy+4x=3,y²+xy-4y+7=0,则xy-1/2(x²+y²
已知2x+y=0,求x-2y/x²+xy*(x²-y²)/x²-4xy+4y
已知2x+y=0,求x-2y/x²+xy乘(x²-y²)÷x²-4xy+4y
已知x²+y²-2x+4y+5=0,求(x²-xy)分之y减去(xy-x²)分之
已知x²+y²-4x-2y+5=0,求代数式[(√x-√y)²+4√xy]/(x+√xy)
已知:x²+y²-4x-2y+5=0,求x+√xy分之(√x-√y)²+4√xy的值.