Răspuns :
[tex]a,b \in N \\
b-a=60 \\
b=2a+13 \\
2a+13-a=60 \\
a+13=60 \\
\boxed{a=49} \\
b-49=60 \\
\boxed{b=109}[/tex]
[tex]a - b = 60 \\
b = a*2 +13\\
a=?\\ b=?\\
a |---------|---60---------|\\
b |---------|---------|-13-| \\
60 - 13 = 47 (a)\\
47 *2+13= 107 ( b)\\
Proba:107 - 47 = 60
[/tex]