若x(y-1)-y(x-1)=4,求【(x²+y²)/2】-xy的值

若(-x+6):(x-y):(4x+y)=3:14:1,求x+y 若(-x+6):(x-y):(4x+y)=3:14:1,求x+y 若x-y=1,求代数式x(x-y)+y(y-x)+2013的值 若x*x+y*y=x+y-1/2,求x,y的值如题 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 已知x×x×y×y+x×x+y×y+1=4xy,求x,y的值快 若x.y满足x+=4和x-y=2,求xy分之2x-y+1除以-x分之y+y分之x的值 已知:【(x²+y²)-(x-y)²+2y(x-y)】/4y=1,求4x/4x²-y²-1/2x+y 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 若x+y=-6,求[(x+y)的2次方-(x-y)的2次方+2y(y-x)]乘以1分之4y (-x+6):(x-y);(4x+y)=3;14:1,求x+y的值. 已知实数x,y满足方程x*x+y*y-4x+1=0.求y-x的最大值 若(x+y)(x+y-1)-2=0,求x+y的值求 若x²-4xy+5y²-2y+1=0,求x,y 若x^5+x^4y+x^4+x+y+1=0,且3x+2y=1,求x,y的值 x>0 y>0 x+y=1,4/X+9/y最小值x>0 y>0 x+y=1,求4/X+9/y最小值 若|x+y-1|+（x-y-2)²=0,求代数式（x+2y)(x-2y）-（2x-y)(-y-2x)的值.