Răspuns :
a + b = 136
a - 6 = b
a = b + 6
b + 6 + b = 136
2 × b + 6 = 136
2 × b = 136 - 6
2 × b = 130
b = 130 : 2
b = 65
a = 65 + 6
a = 71
a + b = 136
a - 6 = b => a - b = 6
adunam relatiile
a + b + a - b = 136 + 6
2a = 142
a = 142 : 2
a = 71
b = 136 - 71
b = 65