若(x+y)²=8,(x+y)²=3 求:(1)xy的值 (2)x²+y²
1/x+1/y=5,求2x-3xy+2y/x²+xy+y的值
若正数x,y满足x²-y²=2xy,求(x-y)/(x+y)的值
若x-y=6,xy=-8,求代数式(x+y+z)²+(x-y-z)(x-y+z)-2·z(x+y)的值
4/X+1/Y=2,XY=-1,求代数式4Y-X/X-2Y/(x+2y-12Y²/x-2y)的值
x/y=3,求x²+y²-xy/x²-y²的值.
若x(x+1)-(x²-y)=-3,求2分之x²+y²-xy的值
已知x/y=3,求x²+2xy-3y²/x²-xy+y²的值
已知y/X=3,求x²-xy+y²/x²+2xy-3y²的值
已知x/y=2,求x²-xy+3y²/x²+xy+6y²的值
已知x+y=4.x-y=6.求代数式xy(y²+y)-y²(xy+2x)-3xy的值
若x²+xy+5y=3,y²+xy+5x=-3,求x+y的值.
若x²+xy+5y=3,y²+xy+5x=-3,求x+y的值