Răspuns :
a + b = 42
a : b = 5
a = 5 × b
5 × b + b = 42
6 × b = 42 | : 6
b = 7
a = 5 × 7
a = 35
a + b = 42
a: b = 5
a = 5 x b
5 x b + b = 42
6 x b = 42 |: 6
b = 7
a = 5 x 7
a = 35
a: b = 5
a = 5 x b
5 x b + b = 42
6 x b = 42 |: 6
b = 7
a = 5 x 7
a = 35