The expression in the image is $8b^3x$, and you are being asked to identify its numerical coefficient.

The numerical coefficient is the constant multiplier of the variable terms in an expression. In this case, the variables are $b^3$ and $x$, so the numerical coefficient is 8, as it multiplies these variables.

Thus, the correct answer is:

8

Would you like any further explanation or details?

Here are 5 related questions to expand on this concept:

1. What is the numerical coefficient of $5a^2b^3$?
2. How do you identify the coefficient in terms like $-7x^2y$?
3. Can a numerical coefficient ever be a fraction or a decimal?
4. What is the numerical coefficient of $3x + 4y$?
5. How does the numerical coefficient change if a term like $2ab^2$ is multiplied by 3?

Tip: Always look for the constant number in front of the variables when identifying the numerical coefficient.