Question

What are the solutions?

Answer 1

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