309. Find the coordinates of the vector $\overline{A B}$, if $A(1; -3; 4)$ and $B(-3; 2; 1)$.
Solution. $\quad X=x_{2}-x_{1}=-3-1=-4, \quad Y=y_{2}-y_{1}=$ $=2-(-3)=5, Z=z_{2}-z_{1}=1-4=-3$. Therefore, $\overline{A B}=$ $=\{-4 ; 5 ;-3\}$.