Point B $\begin{aligned}
& (3 \lambda+1,-\lambda+1,-1) \equiv(2 \mu+2,0, \alpha \mu-4) \
& 3 \lambda+1=2 \mu+2 \
& -\lambda+1=0 \
& -1=\alpha \mu-4 \
& \lambda=1, \mu=1, \alpha=3 \
& B(4,0,-1)
\end{aligned}\text { Let Point ' } P \text { ' is }(2 \delta+2,0,3 \delta-4)\text { Dr's of AP } < 2 \delta+1,-1,3 \delta-3>A P \perp L_2 \Rightarrow \delta=\frac{7}{13}P\left(\frac{40}{13}, 0, \frac{-31}{13}\right)\therefore 26 \alpha(P B)^2=26 \times 3 \times\left(\frac{144}{169}+\frac{324}{169}\right)=216$