Răspuns :
I------------I a
I--------I b a+b=142
I------------I a
I--------I12I b a-b=12
142-12=130
b=130:2=65
a=142-65=77
I--------I b a+b=142
I------------I a
I--------I12I b a-b=12
142-12=130
b=130:2=65
a=142-65=77