Answer:
[tex]\boxed{\sf\:\frac{15\left(75a+76\right)}{76}}[/tex]
Step-by-step explanation:
15 + 25 * a * 45/76
= [tex]\sf\:15 + 25 \times a \times \frac { 45 } { 76 }[/tex]
= [tex]\sf\:15+\frac{25\times 45}{76}a [/tex]
= [tex]\sf\:15+\frac{1125}{76}a [/tex]
= [tex]\boxed{\tt\:\frac{15\left(75a+76\right)}{76}}[/tex]
Hope it helps ⚜