已知x-2y=0,则2x^2÷4y^2

已知x*x+4x+y*y-2y+5=0,则x*x+y*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3x-4y=0,则x^2-y^2/x^2+y^2 已知x^2+y^2-4x+2y+5=0则x^y=? 已知x^2+4x+y^2+2y+5=0,则x^y= 已知X^2+Y^2+16X-4Y+68=0,则X+Y=----------- 已知x²+4x+y²-2y+5=0,则x+y= 已知|5x-y-8|+(7y-x+2)=0则4x+6y 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 已知x²+4y²-4x+4y+5=0,求(2x-y)(x+y)/x四次方-y四次方×xy-y²/2x-y÷(y/x²+y²)² 已知|x+y-3|+(x-y)2=0则 已知x>0,Y>0,如何证x^2/y+y^2/x>=x+y 已知f(x+y,y/x)=x^2-y^2,则f(x,y)= 已知x=y+2,求[(x+y)(x-y)-(x-y)的2次方+2y(x-y)]÷4y的值 已知X^2+Y^2+4X-6Y+13=0,X、Y为实数,则Y^2等于? 已知x,y为实数,根号3x+4 +y^2-6Y+9=0则x+y=? 已知x^2+y^2+13-4x+6y=0,求(2x-y)^2-2(2x-y)(x+2y)+(x+2y)^2 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值