xy=2500 (x-10)(y+1)=2940
xy=(x-10)(y+1) xy=(x-15)(y+3) 解方程组.
[(xy+2)(xy-2)-2x^2y^2+4]/xy,其中x=10,y=-1/25
[(xy+2)(xy-2)-2x^2y^2+4]/(xy),其中:x=10,y=-1/25
若x+y=10 xy=-1 则x²+y²=(x+y)²-2xy=
已知xy>0,证明xy+xy/1+x/y+y/x>=4
1\x+1\y=8\x+y,则y\xy+x\xy=?
已知:xy+x=-1,xy-y=-2.
(x+2y-3xy)-(-2x-y+xy),其中x+y=1/2,xy=-1/2
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y)
已知实数xy,满足10x²-2xy+y²+6x+1=0,求x+y
x y xy=10怎么算