The image contains a mathematical expression that seems to involve logarithms. From what I can make out, the expression is:

$3 \log 4 + \log 5 - \log 40$

It asks for the value of this expression.

Let's simplify this:

1. Using the logarithmic properties:

   • $\log a + \log b = \log(ab)$
   • $\log a - \log b = \log\left(\frac{a}{b}\right)$

2. We begin by applying these properties to the expression:

$3 \log 4 + \log 5 - \log 40$

Step-by-step simplification:

1. The term $3 \log 4$ can be rewritten using the power rule: $\log(4^3) = \log(64)$.

   So, the expression becomes: $\log 64 + \log 5 - \log 40$

2. Combine the first two terms: $\log(64 \times 5) = \log 320$

3. Now, subtract the last term: $\log\left(\frac{320}{40}\right) = \log 8$

So, the final value of the expression is $\log 8$.

If we're looking for a decimal value, $\log 8 \approx 0.9031$ (assuming this is base 10 logarithm).

Would you like further details or have any questions?

Here are 5 related questions to explore:

1. What are the different properties of logarithms?
2. How does the change of base formula work in logarithms?
3. What are some real-world applications of logarithms?
4. How do natural logarithms (ln) differ from common logarithms (log)?
5. How can logarithmic equations be solved algebraically?

Tip: Always remember to check the base of the logarithm when simplifying logarithmic expressions—base 10 (log) and base $e$ (ln) are the most common!