Here goes problem 4 i need help

Desmond wants to sell his car that he paid $8,000 for 2 years ago. the car depreciated, or decreased in value, at a constant rate each month over a 2-year period. if x represents the monthly depreciation amount, which expression shows how much desmond can sell his car for today? \ 8,000 + 24x 8,000 - 24x 8,000 + 2x 8,000 - 2x

Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9

Alex's monthly take home pay is $2,500. what is the maximum bad debt payment he can maintain without being in credit overload?