解方程1/x-1/y=3与1/x^2+1/xy+1/y^2=3
解方程1/x-1/y=3与1/x^2+1/xy+1/y^2=3
解方程:(x^2+1)(y^2+1)=10 (x+y)(xy-1)=3
解方程(1)x^2+2xy+y^2-4x-4y=5,x^2-2xy+y^2-2x+2y=3 (2) xy+x+y=34,
解微分方程题求解微分方程:(1) xy' +2 = (x^3)(y-1)y' 提示:可把x与y 互换而后解原方程(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)
解方程x²-2xy+y²=9,x²+4xy+4y²+x+2y=2 2x-1/y=
已知:x-y=1,xy=-2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
x-y=1,xy=2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
.已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值