Răspuns :
[tex]x - 9 = 20 + 2 = \ \textgreater \ x - 9 = 22 = \ \textgreater \ x = 22 + 9 = \ \textgreater \ \boxed{\boxed{ x = 31 }} = \ \textgreater \
\underline{S = 31}[/tex]
\underline{S = 31}[/tex]