Răspuns :
[tex]a+b=21\\\\
a=2b+ \frac{b}{2} \\\\
2b+ \frac{b}{2} +b=21\\\\
4b+b+2b=42\\
7b=42=\ \textgreater \ b=6\\\\
a=2*6+3\\
a=12+3\\
a=15[/tex]
a=2b+ \frac{b}{2} \\\\
2b+ \frac{b}{2} +b=21\\\\
4b+b+2b=42\\
7b=42=\ \textgreater \ b=6\\\\
a=2*6+3\\
a=12+3\\
a=15[/tex]