The equation of circle passing through point (8,1) and tangent to two coordinate axes

The equation of circle passing through point (8,1) and tangent to two coordinate axes

According to the meaning of the title, the center of the circle is on the straight line y = X
Let the center of the circle be (a, a)
that
√(a-8)²+(a-1)²=a
a²-16a+64+a²-2a+1=a²
a²-18a+65=0
(a-13)(a-5)=0
A = 13 or 5
The equation of circle: (X-13) & sup2; + (y-13) & sup2; = 169 or (X-5) & sup2; + (Y-5) & sup2; = 25