a = numarul de nuci Alexandra
t = numarul de nuci Teodor
b = numarul de nuci Andrei
a + t + b = 81 nuci .
a = t + 3
t = b - 6 ===>> b = t + 6
t + 3 + t + t + 6 = 81
3 × t = 81 - 9
3 × t = 72
t = 72 : 3
t = 24
a = t + 3
a = 24 + 3
a = 27
b = t + 6
b = 24 + 6
b = 30