若x+y>=0,x²+y²
若|x+2y-1|+y²+4y+4=0,求(2x-y)²-2(2x-y)(x+2y)+(x+2y)&
若|x+y-1|+(x-y-2)²=0,求代数式(x+2y)(x-2y)-(2x-y)(-y-2x)的值.
若实数X,Y满足X²+Y²+4X-2Y +1=0,则X²-6X+Y²-2Y的最大
已知x,y满足x²+y²-4x+6y+13=0则(3x+y)²-(3x+y)(3x-y)的
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知非零有理数x,y满足x²-4xy+4y²=0,求x-y/x+y-y-x/x+y的值.
若[x+y-1]+(y+3)²=0,则x-y的值为().
已知y+y'*x²=0,求y=?
若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值
若(x-3)²+|x+y-5|=0,求x²+y²
若|x-2|+x²+1/4y²-xy=0 x= y=
已知x²-x=7,y²-y=7,若x≠y,求x+y的值