已知4x²+4xy+y²-4x-2y+1=0,求证2x²+3xy+y²-x-y=
已知X²+Y²+X²Y²-4XY+1=0 求:(X-Y)^2008-(XY)^2
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知2X-3√xy-2y=0(x>0)求2x²+xy-9y²分之x²+4xy-16y
已知x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy
已知x²-3xy+4x=3,y²+xy-4y+7=0,则xy-1/2(x²+y²
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
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+3xy-4y²=0,求(x-2y)除以(x+2y)的值
已知x²+2xy+y²-x-y+1/4=0
已知(x+y-7)²+|2x-3y-4|=0 求xy得值
2x+y=0,求4x²+2xy(x+y)+y³