How much is a cheap flight from London to Salt Lake City if pre booked 6 months in advance?

It would be a single flight as would then go to LA.

(ALSO do you know how much a cheap flight is from Salt Lake to LA?)How much is a cheap flight from London to Salt Lake City if pre booked 6 months in advance?
I found some flights on Dohop in June for $765, check it out here: http://www.dohop.com/flights/?a1=LTN%2CL鈥?/a>How much is a cheap flight from London to Salt Lake City if pre booked 6 months in advance?
Have a look on the airlines website...