If the Cowboys lose out and the Eagles win out they will be tied at 10-7. They will have split their games. They will both be 4-2 in the division. They will have the same record against common opponents. They will both be 8-4 in the conference. So it comes down to strength of victory, or the records of the teams beaten be each of the teams that are tied.
Right now Dallas has a big lead in strength of victory. 67-78 to 58-88, or .462 to .397.
The teams that matter in this calculation are the Chargers, New England, Minnesota, The Giants, Washington, Detroit, The Jets, and Denver. This assumes the Cowboys lose out and the Eagles win out.
If the Chargers, New England, Minnesota and the Giants lose out and Detroit, Jets, and Denver win out while Washington beats Dallas and the Giants and loses to the Eagles, the Eagles strength of victory would increase to .434 while Dallas's would drop to .422. The Eagles would win the division.
There are too many permutations to go through with each of these teams having 3 games left but it is unlikely the Jets and Lions will win out and the Chargers and New England would lose out. The Cowboys only need the Chargers, New England, Minnesota, and the Giants to win 3 games OR Detroit, Jets, and Denver to lose 3 games to win the division.
If you are curious, Detroit plays Atlanta, Seattle and Green Bay. The Jets play Jacksonville, Tampa Bay and Buffalo. Denver plays Las Vegas, Chargers and KC.
Meanwhile, the Chargers have Houston, Denver, and Las Vegas. New England has Buffalo, Jacksonville and Miami. The Vikings have LA Rams, Green Bay and Chicago.
Looking at these schedules the likelihood is Dallas wins the strength of victory tie breaker if it comes to that.
But I think Dallas will beat Washington this week and all of this will be moot.