I am having trouble here using the this A x B (cross product)/A to derive the distance from this point (4, 1, -2) to x= 1 +t, y = 3-2t, z = 4-3t.
The correct formula is $\displaystyle \ell :P + tD\;\& \,d(\ell ,Q) = \frac{{\left\| {\overrightarrow {PQ} \times D} \right\|}}{{\left\| D \right\|}}$.
In this problem $\displaystyle Q(4,1,-2),~P(1,3,4)~\&~D=<1,-2,-3>$