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

Substitute x = r cos(θ) and y = r sin(θ) into the equation: (r cos(θ) + 3)² + (r sin(θ))² = 9. Expanding and using cos²(θ) + sin²(θ) = 1 gives r² + 6r cos(θ) = 0, or r(r + 6 cos(θ)) = 0. The circle is represented by r = −6 cos(θ), choice A.

AI-written and checked against the verified answer.