求(X+Y)(X-Y)(X²+Y²),X=5 Y=2,
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知x²+y²+5=2x+4y,求代数式(2x²-(x+y)(x-y))x((x+y-1)
已知x²+y²-2x+4y+5=0,求x+y
已知x² +y²+5/4=2x+y,求y-x的值
已知x²+4x+y-2y+5=0求x+2y
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.
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x,y的值满足方程组x+2y=3,x-y=-2,求x/(x-y)²+x²-y²/(x+
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²