Question

Need an explanation to this equation? Radius how do I find it?

Answer 1

`x^2-10x+y^2+6y-30=0`

Now, the circle equation

`\left(x−a\right)^2+\left(y−b\right)^2=r^2\:\:\mathrm{is\:the\:circle\:equation\:with\:a\:radius\:r,\:centered\:at}\:\left(a,\:b\right)`

Rewrite in standard form

`\left(x-5\right)^2+\left(y-\left(-3\right)\right)^2=8^2`

Therefore the circle properties

`\left(a,\:b\right)=\left(5,\:-3\right),\:r=8`

The final answer

`\mathrm{Circle\:with\:center\:at}\:\left(5,\:-3\right)\:\mathrm{and\:radius}\:r=8`