Answer :

[tex]x^{2} + 8x + 6 = 0 \\x = \frac{-(8) +/- \sqrt{(8)^{2} - 4(1)(6)}}{2(1)} \\x = \frac{-8 +/- \sqrt{64 - 24}}{2} \\x = \frac{-8 +/- \sqrt{40}}{2} \\x = \frac{-8 +/- 2\sqrt{10}}{2} \\x = -4 +/- \sqrt{10}[/tex]
[tex]x = -4 + \sqrt{10}[/tex]    [tex]x = -4 - \sqrt{10}[/tex]

It is equal to D.