It's the third option.
Completing the square yields
x ² + 9x + 7 = 0
(x ² + 9x + 81/4) + 7 = 81/4
(x + 9/2)² + 7 = 81/4
Now solving for x gives
(x + 9/2)² = 53/4
x + 9/2 = ± √(53/4) = ± √53/2
x = (-9 ± √53)/2
