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Question
Find the centre and radius of each of the following circles:
(x + 5)2 + (y + 1)2 = 9
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Solution
Let (h, k) be the centre of a circle with radius a.
Thus, its equation will be
\[\left( x - h \right)^2 + \left( y - k \right)^2 = a^2\]
Given:
(x + 5)2 + (y + 1)2 = 9
Here, h = −5, k = −1 and radius = 3
Thus, the centre is (−5, −1) and the radius is 3.
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