已知x²+y²-2x+4y=-5,求x.y
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(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
已知x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知2x-y=10,求式子[(x^2+y^2)-(x-y)^2+2y(x-y)]/4y (4xy-2y²)/4
已知:4x = 5y,求(x+y) :y
已知x²+y²+13-4x+6y=0,求(2x-y)²-2(2x-y)(x+2y)+(x+
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(