American odds can be calculated for underdogs simply by dividing the odds by 100 and multiplying that product by the bet amount. For favorites, divide 100 by the odds and multiply that product by the bet amount. In both cases, you ignore the plus or minus sign in front.
Bet $50 on the Panthers at -125 and the potential payout will equal (100/125) x 50. That works out to $40. Bet $50 on the Panthers at +125 and the potential payout will equal (125/100) x 50. That works out to $62.50.