Răspuns :
a - b = 5 ==> a = b + 5 (1)
a + b = 25
Inlocuim in aceasta ecuatie relatia (1):
b + 5 + b = 25
2b = 20
b = 10
a = b + 5 = 15
a + b = 25
Inlocuim in aceasta ecuatie relatia (1):
b + 5 + b = 25
2b = 20
b = 10
a = b + 5 = 15