Since k is constant (the same for every point), we can find k when given any point by dividing the y-coordinate by the x-coordinate.
Given the center
and the radius
of a circle, its equation is

In your case, the center is (-4,0), and the radius is 2. Plug these values into the generic formula and you'll get the equation.
Answer:
The last one is the answer; The slope of AB is different than the slope of BC.
Step-by-step explanation: