Question 3 Move the center of the circle vertically so it lies above and then below the x-axis. How does the equation of the circle change as the center crosses
the x-axis?

 The variable k changes as the center of the circle moves vertically. The sign of k is positive when the center is below the x-axis and negative when it is above the x-axis. The sign of the variable k flips when the center moves across the x-axis.

Step-by-step explanation: plato/edmentum answer!

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