圆x^2+y^2+2x-8y+8=0的圆心坐标和半径分别为（）

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 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 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) 两圆x^2+y^2-6x+16y=0与x^2+y^2+4x-8y-44=0的公切线条数 已知两圆x+y-2x+10y-24=0和x+y+2x+2y-8=0.求公共弦的长度 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^2+y^2-16x-8y+25=0,求y/x-x/y的值 已知x平方+y平方+6x-8y+25=0,求y/x+x/y-2的值. 若x,y为正数,且2*x+8*y-x*y=0,求x+y的最小值 与圆x^2+y^2-4x=0外切,又与y轴相切的圆的圆心轨迹方程是A.y^2=8x B.y^2=8x(x>0)和y=0 C.y^2=8x(x>0) D.y^2=8x(x>0)和y=0(x x^2+2x+y^2-8y+16=0,求y/x的值 x'2+2x+y'2-8y+17=0,求x'y的值 2x+8y-xy=0(x>0,y>0),求x+y的最小值