已知x²+4x+y-2y+5=0求x+2y

已知x²+y²-2x+4y+5=0,求x+y 已知x²+4x+y-2y+5=0求x+2y 已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y 已知x^2+4y^2-4x+4y+5=0,求(y^4-x^4)/(y-2x)(x+y)*2x-y 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知x²+y²-2x+4y+5=0,求X^4-y^4/2x^2+xy-y²·2x-y/xy 已知x²+y²+5=2x+4y,求代数式（2x²-（x+y)(x-y))x((x+y-1) 已知x² +y²+5/4=2x+y,求y-x的值 已知x,y>0 2x+y+3=xy 求5x+4y最小值