X²+y²一10X一12y+61=0
(X²—10X+25)+(y²一12y+36)=0
(X—5)²十(y—6)²=0
(X一5)²=0
(y—6)²=0
X=5
y=6
X÷y=5÷6=5/6
y÷X=6÷5=6/5=1又1/5