Final answer:
The equation that represents circle b, obtained by shifting circle a down by 2 units, is A) x^2(y + 2)^2 = 49.
Step-by-step explanation:
The equation x^2(y - 1)^2 = 49 represents a circle that can be obtained by shifting circle a down 2 units in the xy-plane. When you shift a circle down by 2 units, you adjust the y-coordinate in the equation by adding 2 to it because the center of the circle moves from (0, 1) to (0, -1). Hence, the modified equation becomes x^2(y + 2)^2 = 49.
Thus, the correct answer to the question 'which of the following equations represents circle b?' is A) x^2(y + 2)^2 = 49.