Find the centre and radius of the circle (x + 5)2 + (y – 3)2 = 36
Question:

Find the centre and radius of the circle $(x+5)^{2}+(y-3)^{2}=36$

Solution:

The equation of the given circle is $(x+5)^{2}+(y-3)^{2}=36$.

$(x+5)^{2}+(y-3)^{2}=36$

$\Rightarrow\{x-(-5)\}^{2}+(y-3)^{2}=6^{2}$, which is of the form $(x-h)^{2}+(y-k)^{2}=r^{2}$, where $h=-5, k=3$, and $r=6$.

Thus, the centre of the given circle is (–5, 3), while its radius is 6.