Answer:
[tex]\boxed{x-5}[/tex]
Step-by-step explanation:
[tex]f(x) = x^2 - 8x + 15 \\g(x) = x - 3[/tex]
[tex]\frac{f(x)}{g(x)}[/tex]
[tex]\frac{x^2-8x+15}{x-3}[/tex]
[tex]\frac{(x-3)(x-5)}{x-3}[/tex]
[tex]\frac{x-5}{1}[/tex]