已知xy≠1,5x2+2001x+9=0,9y2+2001y+5=0,求xy
已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以(x2+y2/x
已知:x2+5y2-4xy-6y+9=0,求x、y的值.
已知x2+y2-4x+6y+13=0,求x2-6xy+9y2的值.
已知2x2+5xy-3y2=0且xy不等于0,求x:y的值
已知x-y=9,xy=5,求x2+y2的值
已知x2+y2=9,xy=-3,求多项式5x²-3xy-5y²-11xy-8x²+2y
已知x>y>0,且xy=1,求 (x2+y2)/(x-y)的最小值,
已知2+4y2-4x+4y+5=0,求x四次方-y的四次方/xy乘以2x2-xy/xy-y2除以(y分之x2+y2)2
已知x2+y2-2x+4y+5=0,求(x^4-y^4)/(2x^2+xy-y^2)·[(2x-y)/(xy-y^2)]
已知X2-2x+y2+6y+10=0,求(x2-2xy)/(xy+y2)的值
已知2x-3*根号(xy)-2y=0(x>0),则x2+4xy-16y2除以2x2+xy-9y2的值是多少?
已知x2-2xy=3y2且x,y为非零实数 求:(1)2x+y/x-2y (2)2x2-3y2+5xy/x2+xy+y2