Let L_1: (x-1)/3=(y-1)/-1=(z+1)/0 and L_2: (x-2)/2=y/0=(z+4)/(α), α ∈ R, be two lines, which intersect at the point B. If P is the foot of…

Let $\displaystyle \mathrm{L}_1: \frac{x-1}{3}=\frac{y-1}{-1}=\frac{z+1}{0}$ and $\displaystyle \mathrm{L}_2: \frac{x-2}{2}=\frac{y}{0}=\frac{z+4}{\alpha}, \alpha \in \mathbf{R}$, be two lines, which intersect at the point B . If P is the foot of perpendicular from the point $\displaystyle \mathrm{A}(1,1,-1)$ on $\displaystyle \mathrm{L}_2$, then the value of $\displaystyle 26 \alpha(\mathrm{~PB})^2$ is $\displaystyle \_\_\_\_$.