_____ The constant term is all you really need to look at to figure this. For P(x), the constant is +2. For Q(x), the constant is -6.
For P+Q, the constant is -4 . . . . not correct For Q-P, the constant is -8 . . . . correct For PQ, the constant is -12 . . . . not correct For P-Q, the constant is 8 . . . . .not correct
10 inches because there are 4 sides of a square so, if the perimeter is 40 inches, to figure out the side lengths you just have to divide the perimeter by 4
