What is the polar form of (x + 3)2 + y2 = 9?

Expand the equation: (x + 3)² + y² = 9 becomes x² + y² + 6x = 0. Substitute x² + y² = r² and x = r cos(θ), giving r² + 6r cos(θ) = 0. Factoring out r and using the circle’s polar equation gives r = −6 cos(θ), which is choice A.

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