What is the possessive form of harmonica​

Two numbers have a sum of -19. one number is x. what expression represents the other number?

Find solution of the linear equation y = 2/3x + 1/3

90.0% complete a b c d e confirm last week, your delivery runs took 7 hours 12 minutes on monday, 6 hours 46 minutes on wednesday, and 6 hours 53 minutes on friday. what was your average time for a delivery run?