Notam numarul de mere a lui Alina cu x si ale lui Nicu cu y !
[tex]x+y=71=\ \textgreater \ x=71-y \\ y+9=4x =\ \textgreater \ y+9 = 4(71-y)=\ \textgreater \ y+9=284-4y \\ y+4y=284-9=\ \textgreater \ 5y=275=\ \textgreater \ y=55 \\ =\ \textgreater \ x=71-55=\ \textgreater \ x=16[/tex]
