A (+7) on an NFL betting line indicates a seven-point underdog in the point spread. For example, you might see an NFL line that looks like this:
Tampa Bay (-7) (-110)
Dallas (+7) (-110)
In this point spread, the Tampa Bay Buccaneers are playing the Dallas Cowboys. You can either pick the favored Bucs with seven points subtracted from their final score, or pick the under dog Cowboys with seven points added to their final total.
If the Buccaneers win by more than seven points, Tampa Bay bettors win on the point spread. If the Bucs win by six or less, or the Cowboys win outright, then Dallas bettors win on the poijnt spread.
If Tampa Bay wins by exactly seven points, the bet is a push, and you would get the amount of your wager returned to you. Both sides of this bet pay at (-110) odds, meaning you would have to bet $110 to win $100.