8 I think sorry if im wrong
Answer:

Step-by-step explanation:

f⁻¹(x) = f(y) = 5y - 1 = x

Since it doesn't mention multiplication, no. What would be the point of rewriting an expression from 3-2 to 3+(-2)?
Well, each one takes two minutes, regardless of how many brothers there are. If it takes 2 minutes per paper, then the answer is simply 147*2. Which is 297 minutes. Even if one of them was delivering papers, the answer would be the same. These extra numbers are put in there to confuse you. Dont forget that, be careful what you read.