Odpowiedź:
x + x + x = 30
3x = 30
x = 10
x + y + x = 380
2x + y = 380
20 + y = 380
y = 360
360 + z + z = 266
360 + 2z = 266
2z = -94
z = -47
x + y + z = -47 + 360 + 10 = 323
