l1(t)⎧⎩⎨x=1+2ty=−4+3t,z=2+t

l2 is the parallel line that passes through the point (2,6,−2).

a. Find a pair of points (one on each line) that are as close as possible.

b. Find the distance between the lines l1 and l2.

c. Justify why the points you found in a. are as close as possible.