若x^2+y^2+4x-8y+20=0,求分式x^2-y^2/xy的值

若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 若实数x、y满足x平方+y平方-4x-2y+5=0,求根号8y-2x分之（根号x）+y 若实数X,Y满足x²+y²-4x-2y+5=0求√x+y/√8y-2x 若x-y=1 化简（x+y)(x^2+y^2)(x^4+y^4)(x^8+y^8)(x^16+y^16) 若x^2+4x+y^2-8y+20=0,则y^x的值是? 【初一数学】若x^2+4x+y^2+8y+20=0,求x,y 已知x.x+y.y+8x+6y+25=0,求代数式(x.x-4y.y)/(x.x+4xy+4y.y)-x/(x+2y)的值 若x-y不等于0,2x-3y=0,则分式(10x-11y)/(x-y)的值是（）?(10x-11y)/(x-y) =[(8x-8y)+(2x-3y)]/(x-y) =8为什么8X-8Y=8？(10x-11y)/(x-y)=[(8x-8y)+(2x-3y)]/(x-y)=8+(2x-3y)]/(x-y)=8+0=8 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 x*x+2x+y*y-4y+5=0 x= y= {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? RT,若（√2x-y）+y^2+4y+4=0,求[(x-y)^2+(x+y)(x-y)]÷2x的值 [(x+2y)(x-2y)-(x-2y)^2+8y(x+y)]除以4x= x*x+2x-y*y+6y-8=0,x+y不等于2,求x-y的值