3x² + 3y² - 11x = -91
Divide through by 3
x² + y² - 11/3 x = -91/3
x² - 11/3 x + y² = -91/3
(x² - 11/3 x ) + y² = -91/3
[x² - 11/3 x +(-11/6)² ] + y² = -91/3 + (- 11/6)²
(x - 11/6)² + y² = -91/3 + 121 / 36
Comparing this with (x-a)² + (y-b)² = r²
r² = -971/36
Taking the square root will give an immaginary number
The radius is NOT a real number
This equation does not have a real radius