判定圓x^2+y^2-6x+4y+12=0與圓x^2+y^2-14x-12y+14=0是否相切?

判定圓x^2+y^2-6x+4y+12=0與圓x^2+y^2-14x-12y+14=0是否相切?

X2+Y2-6X+4Y+12=0,
(x-3)²+(y+2)²=1²圓心是(3,-2),半徑是1
X2+Y2-14X-2Y+14=0
(x-7)²+(y-1)²=6²圓心是(7,1),半徑是6
圓心距為5,
所以兩圓內切!