Răspuns :
a + b = 25
a - b = 5
Adunam relatiile
a + b + a - b = 25 + 5
2a = 30
a = 30 : 2
a = 15
b = 10
a + b = 25
a - b = 5
a = 5 + b
5 + b + b = 25
5 + 2 × b = 25
2 × b = 25 - 5
2 × b = 20
b = 20 : 2
b = 10
a = 5 + 10
a = 15
a + b = 25
a - b = 5
Adunam relatiile
a + b + a - b = 25 + 5
2a = 30
a = 30 : 2
a = 15
b = 10
a + b = 25
a - b = 5
a = 5 + b
5 + b + b = 25
5 + 2 × b = 25
2 × b = 25 - 5
2 × b = 20
b = 20 : 2
b = 10
a = 5 + 10
a = 15