1. When $x=\frac{\sqrt{21}-5}{2}$, the value of the algebraic expression
$$
x(x+1)(x+2)(x+3)(x+4)(x+5)
$$

is $\qquad$ .
$$
\text { II. 1. }-15 \text {. }
$$

From $2 x+5=\sqrt{2 \mathrm{i}}$, after rearrangement, we get
$$
\begin{array}{l}
x^{2}+5 x+1=0 . \\
\text { Therefore, } x(x+5)=-1 . \\
\text { Also, } (x+1)(x+4)=x^{2}+5 x+4=3, \\
(x+2)(x+3)=x^{2}+5 x+6=5 .
\end{array}
$$

Thus, multiplying the equations, the value sought is -15.