x+4)^2+y^2=(r+5)^2=r^2+10r+25
(x-4)^2+y^2=(r+1)^2=r^2+2r+1
16x=8r+24
2x=r+3
r=2x-3
圆心轨迹(x-4)^2+y^2=(x-1)^8
x^2-8x+16+y^2=8x^2-16x+8
7x^2-8x-y^2=8
x+4)^2+y^2=(r+5)^2=r^2+10r+25
(x-4)^2+y^2=(r+1)^2=r^2+2r+1
16x=8r+24
2x=r+3
r=2x-3
圆心轨迹(x-4)^2+y^2=(x-1)^8
x^2-8x+16+y^2=8x^2-16x+8
7x^2-8x-y^2=8