Convert (x−3)^2+y^2=9 to polar form.

(x -3)^2  +y^2  =  9

( rcos θ  - 3)^2  + (rsinθ)^2   = 9

r^2cos^2θ - 6rcosθ + 9  + r^2 sin^2θ  = 9      subtract 9 from both sides

r^2 ( sin^2 θ  + cos ^2 θ)  - 6r cosθ  =  0

r^2 (1)   =  6r cosθ      divide out r

r  = 6cosθ