If you make A1 the first term in the sequence you must use (n-1) in the explicit formula. If you go backwards in the sequence to find A0 = 2 then you would use n.
The don't have A0 = 2 listed as an option so we use A1 = -4 and (n-1) terms.
Answer: The − sign here means subtraction. However, recall that 4 − 7 can be rewritten as 4 + (−7), since subtracting a number is the same as adding its opposite.
