圆x^2+y^2-2x+6y+8=0的周长等于多少

x*x+2x-y*y+6y-8=0,x+y不等于2,求x-y的值 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 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) 已知X*X+Y*Y+6X-8Y+25=0 求（Y/X)+(X/Y)-2=? 已知x^2+y^2-6x-8y+25=0,求分式y/x - x/y的值 已知x^2+y^2-6x-8y+25=0 求y/x-x/y的值 已知x,y满足x^2+y^2-6x+8y+25=0,求y^x的值 若x^2+y^2-6x+8y+25=0 则y/x-x/y的值是 已知x平方+y平方+6x-8y+25=0,求y/x+x/y-2的值. 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x,y 满足x(x-2)-y(y-6)=-10,求x,y的值 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)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 两圆x^2+y^2-6x+16y=0与x^2+y^2+4x-8y-44=0的公切线条数 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 x^2+4y^2-6x+4y+10=0,求x^4-y^4/(x+2y)(x-2y)*x+2y/xy^2+y^3除以（x^2+y^2/y)^2的值 求f(x,y)=x+y+7的最大值,使(x,y)满足x+2y≤10,2x+y≥6,y≥0