372. Form the equation of the plane passing through the point $M_{0}(1 ; 2 ; -1)$ and perpendicular to the vector $\bar{n}\{3 ; 0 ; 2\}$.
Solution. Applying formula (4), we get

$$
3(x-1)+0(y-2)+2(z+1)=0
$$

or

$$
3 x+2 z-1=0
$$

The desired equation of the plane does not contain $y$, i.e., it is the equation of a plane parallel to the $O y$ axis.