It's the first one lmk if you want an explanation
You would have no problem at all if it said "7 cows minus 2 cows", or "7 books minus 2 books". The THINGS just happen to be m's instead of cows or books.
Required potynomial = (x -5)(x - 3 - 2i)(x - 3 + 2i) = (x - 5)(x^2 - 6x + 13) = x^3 - 6x^2 + 13x - 5x^2 + 30x - 65 = x^3 - 11x^2 + 43x - 65