The mathematical expression in the image is:

$\frac{3a - 6}{3a}$

Simplifying the Expression:

1. Factor out the numerator, $3a - 6$: $3a - 6 = 3(a - 2)$

   So the fraction becomes: $\frac{3(a - 2)}{3a}$

2. Cancel the common factor $3$ in the numerator and denominator: $\frac{a - 2}{a}$

Final Answer:

$\frac{a - 2}{a}$

Would you like further details, such as an explanation of factoring or simplifying fractions? Let me know!

Here are 5 related questions for further exploration:

1. What happens if $a = 0$ in this fraction? Why is it undefined?
2. How would you simplify $\frac{4x - 8}{4x}$ using a similar process?
3. What is the domain of $\frac{a - 2}{a}$?
4. How do you simplify complex fractions involving polynomials?
5. What is the importance of factoring when simplifying rational expressions?

Tip: Always check for values that make the denominator zero to avoid undefined expressions.