X = [1,2,4,5,8]
Y = [1,3,6,9]
Z = [6,8,14,16]

print('Løsning 1')

for x in X:
    for y in Y:
        for z in Z:
            if z == x + y:
                print((x, y, z))

print('Løsning 2')

answer = [(x, y, z)
          for x in X
          for y in Y
          for z in Z
          if z == x + y]
print(answer)

print('Løsning 3')

answer = [(x, y, x + y)
          for x in X
          for y in Y
          if x + y in Z]
print(answer)

print('Løsning 4')

answer = [(x, y, z)
          for x in X
          for y in Y
          if (z := x + y) in Z]
print(answer)