1. In the expansion of the polynomial $(x-1)^{3}(x+2)^{10}$, the coefficient of $x^{6}$ is $\qquad$ .
-、1. -4128 .
The coefficient of $x^{6}$ is
$$
2^{7} \mathrm{C}_{10}^{3}-3 \times 2^{6} \mathrm{C}_{10}^{4}+3 \times 2^{5} \mathrm{C}_{10}^{5}-2^{4} \mathrm{C}_{10}^{6}=-4128
$$