The expression shown in the image is:

$5b^3 \cdot 5b^3$

To simplify this expression:

1. Multiply the constants: $5 \times 5 = 25$.
2. Use the property of exponents: when multiplying powers of the same base, add the exponents. Here, $b^3 \times b^3 = b^{3+3} = b^6$.

So, the simplified expression is:

$25b^6$

Let me know if you would like any further explanations or details. Here are five related questions:

1. How do you handle exponents when dividing powers of the same base?
2. What happens when you raise a power to another power (e.g., $(b^3)^2$)?
3. How can you simplify expressions with multiple variables, like $5b^3c^2 \cdot 2b^2c^3$?
4. What is the rule for multiplying square roots of variables?
5. How would you expand $(5b^3)^2$?

Tip: Remember that multiplying powers with the same base only works when adding their exponents; the base must remain the same.