2x3 - 4x + 2y2 - 6y - 2 = 0
Divide through by 2: x2 - 2x + y2 -3y -1 = 0
x2 -2x + y2 - 3y = 1
x2 -2x + 1 + y2 - 3y + 9/4
= 1+ 1 + 9/4
= (x- 1)2 (y - 3/2)2
= √[17/4]
r = √17/2