How do you find the center and radius of the circle: #(x - 6)^2 + y^2 = 49#?
Slightly reformulate in standard form to find that the centre is at
This equation is essentially the same as:
#(x-6)^2+(y-0)^2 = 7^2#
which is in the standard form:
#(x-h)^2+(y-k)^2 = r^2#
... the equation of a circle with centre
So the centre of our example circle is