Answer:
Step-by-step explanation:
The equation of a circle in the standard form:
[tex](a-h)^2+(y-k)^2=r^2[/tex]
(h, k) - center
r - radius
We have the equation:
[tex]x^2+y^2-12y-15=0[/tex]
Convert into a standard form using
[tex](a-b)^2=a^2-2ab+b^2\qquad(*)[/tex]
[tex]x^2+\underbrace{y^2-2(y)(7)+7^2}_{(*)}-7^2-15=0\\\\(x-0)^2+(y-7)^2-49-15=0[/tex]
[tex](x-0)^2+(y-7)^2-64=0[/tex] add 64 to both sides
[tex](x-0)^2+(y-7)^2=64[/tex]
The center (0, 7)
The radius: r = √64 = 8
