First we need to convert the given equation to standard form, then we can write the center and radius directly from it.
[tex] x^{2} -16x+ y^{2} -36=0 \\ \\
x^{2} -2(x)(8)+ y^{2} = 36 \\ \\
x^{2} -2(x)(8)+ 8^{2}+ y^{2} =36 +8^{2} \\ \\
(x-8)^{2}+y^{2}=100 [/tex]
Thus, we can say now:
Center of the circle is (8,0) and its radius is 10.