Find the centre and radius of the circle .

Answer and explanation

Correct answer: B.

  1. Step 1: Complete the square in and in to get the form . Step 2. The centre is and , so the radius is 5. **Answer: . Why not the others:** : The centre's signs are reversed. : That gives instead of . : That uses the coefficients of and without halving them.

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Find the centre and radius of the… | Singapore GCE O-Level