not quite sure but maybe it will help ;)

Tanya to be seated at head of table, which means she can sit at either end.. so there are 2 ways to seat her.

Holding her spot constant, there are 9! ways to seat the rest of the people.

but Henry can't sit beside Nancy or Wilson, so find out how many ways Henry can be seated with either (a)Nancy or (b)Wilson MINUS the times when they are all seated together(c), then subtract this from the total.

(a) = 6!

(b) = 6!

(c) = 5!

So I think the answer is 2+(9!-2x6!+5!)