Distance Between Line Intersections

Let a line having direction ratios 1,−4,2 intersect the lines ‌

x−7

3

=‌

y−1

−1

=‌

z+2

1

and ‌

x

2

=‌

y−7

3

=‌

z

1

at the points A and B. Then (AB)2 is equal to__