A circle with equation x^2+y^2-2x+8y-40=0. Find the circle centre and the radius

2g=-2, -g=1. 2f=-8, -f=4. cc(-2,4). r=√(g^2+f^2-c)=√(4+16+40)=√80=4√5

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Answered by Liam M. Maths tutor

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