Vector parallel to L $\begin{aligned}
& =\left|\begin{array}{ccc}
\hat{i} & \hat{j} & \hat{k} \
2 & 1 & -2 \
1 & 3 & 4
\end{array}\right|=10 \hat{i}-10 \hat{j}+5 \hat{k} \
& =5(2 \hat{i}-2 \hat{j}+\hat{k})
\end{aligned}Equationof′L′\frac{x-2}{2}=\frac{y+1}{-2}=\frac{z-3}{1}=\lambda(\text { say })LetQ(2 \lambda+2,-2 \lambda-1, \lambda+3)\begin{aligned}
& \Rightarrow \quad 2 \lambda+2=0 \Rightarrow \lambda=-1 \
& \Rightarrow Q(0,1,2) \
& d(P, Q)=3
\end{aligned}$