With center (-6,7), tangent to the y-axis

Question

With graph 

Answer 1

If you're looking for the equation of a circle with center (-6, 7) and tangent to the y-axis, then

 

Because the circle is tangent to the y-axis, then the radius is 6 because it's the distance from the center to the y-axis.

So the equation of the circle is:

(x – h)2 + (y – k)2 = r2,  where (h,k) is the center

(x + 6)² + (y - 7)² = 36