Răspuns :
[tex]\it \dfrac{a}{3}= \dfrac{4}{5}\ \stackrel{derivare}{\Longrightarrow}\ \dfrac{a+3}{3}= \dfrac{4+5}{5} \Rightarrow \dfrac{a+3}{3}=\dfrac{9}{5}[/tex]
[tex]\it \dfrac{a}{3}= \dfrac{4}{5}\ \stackrel{derivare}{\Longrightarrow}\ \dfrac{a+3}{3}= \dfrac{4+5}{5} \Rightarrow \dfrac{a+3}{3}=\dfrac{9}{5}[/tex]