Answer
$\\(x+2)^2+y^2=36$
Work Step by Step
RECALL:
The standard form of the equation of a circle with a center of $(h, k)$ and a radius of $r$ units is:
$(x-h)^2 + (y-k)^2 = r^2$
The given circle has its center at $(-2, 0)$ and a radius of $6$ units.
Use the standard form above where $h=-2$, $k=0$ and $r=6$ to obtain:
$[x-(-2)]^2 + (y-0)^2 =6^2
\\(x+2)^2+y^2=36$