x-y=1,求x²-y²-2y
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y
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=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
4/X+1/Y=2,XY=-1,求代数式4Y-X/X-2Y/(x+2y-12Y²/x-2y)的值
若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值
已知x²+y²+5=2x+4y,求代数式(2x²-(x+y)(x-y))x((x+y-1)
已知实数x,y满足x²+y²-xy+2x-y+1=0 求x y
已知{(x²+y²)-(x-y)²+2y(x-y)}÷4y=1,求4x²-y
已知x+y=1,xy=-二分之一,求x(x+y)(x-y)-x(x+y)²
已知x²+x*y=-1,x*y+y²=2,试求2x²-x*y-3y²的值
(1)已知x+y=6,x²-y²=5,求x-y的值(2)若x+y=3,x²+y²