8 $\left(x^{2}+x-\frac{1}{x}\right)^{6}$ The constant term in the expansion is
. (Answer with a specific number)
$8-5$ Hint: From the condition, the constant term is $\mathrm{C}_{6}^{2}(-1)^{4}+\mathrm{C}_{6}^{3}(-1)^{3}=-5$.