I assume your question was to simplify the following fraction ;
[tex]{:\implies \quad \sf \dfrac{4a+3}{5}-\dfrac{2a+3}{3}}[/tex]
Taking LCM will yield ;
[tex]{:\implies \quad \sf \dfrac{3(4a+3)-5(2a+3)}{15}}[/tex]
[tex]{:\implies \quad \sf \dfrac{12a+9-10a-15}{15}}[/tex]
[tex]{:\implies \quad \boxed{\bf \dfrac{2a-6}{15}}}[/tex]
This is the required answer