The circle passes through the points (-4,8),(4,-4), and(3,-9).
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You didn't say what you want to do.
If you want to find the equation of the circle:
Label the points A(-4,8), B(4,-4), and C(3,-9).
Find the perpendicular bisector of AB and of BC.
Find the intersection of the 2 bisectors, that's the center of the circle (h,k).
The distance from the center to any point is the radius.
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That's one way to do it.
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I prefer to use a matrix.
| x^2+y^2 x y 1|
|x1^2+y1^2 x1 y1 1|
|x2^2+y2^2 x2 y2 1| = 0
|x3^2+y3^2 x3 y3 1|