[Haskell-beginners] Do I understand this well

Hello, Im stil reading chapter4 Now we have this : addVectors (x1, y1) (x2, y2) = (x1 + x2, y1 + y2) do I understand it that the outcome of x1+x2 will be saved in the last expression x1 + x2 But on which variable can the outcome be found. Roelof