A student is solving a quadratic equation. To solve for x, he applied the quadratic formula, replacing a, b, and c with the correct coefficients:

$\displaystyle{x}=\frac{{-{5}\pm\sqrt{{{25}-{4}{\left({6}\right)}{\left({8}\right)}}}}}{{{2}{\left({6}\right)}}}\usepackage{cmbright}\Huge\$

In the equation he is solving, what is the value of b?