First, we can bring both fractions under the common denominator (a - 3)(a - 5):
![(4)/(a-3)\Big((a-5)/(a-5)\Big) +(9)/(a-5)\Big((a-3)/(a-3)\Big)\\\\=(4(a-5)+9(a-3))/((a-3)(a-5))](https://img.qammunity.org/2019/formulas/mathematics/middle-school/mbc33wsvgdqc3j3vxrv5lix7rh48t3z7hf.png)
Looking at the numerator, we can distribute and collect like terms:
![4(a-5)+9(a-3)=4a-20+9a-27=13a-47](https://img.qammunity.org/2019/formulas/mathematics/middle-school/2zolsn5sv45fqipi2q8pyzk36h93tiiych.png)
and looking at the denominator, we can do the same:
![(a-3)(a-5)=(a-3)a+(a-3)(-5)\\=a^2-3a-5a+15\\=a^2-8a+15](https://img.qammunity.org/2019/formulas/mathematics/middle-school/fvh3qiskjwz6llllcmib7k2jp8z8n247ts.png)
With these simplified expressions, the final fraction becomes
![(13a-47)/(a^2-8a+15)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/z8hx05um6mginmrhfkfelwp1844w8xc5c9.png)