Answer :

Let's reduce the given expression step by step. The expression is:

[tex]\[ E = 36^{\log_7 \left( 3^{(\log_5 7 \times \log_3 5)} \right)} \][/tex]

First, we need to simplify the exponent [tex]\( \log_7 \left( 3^{(\log_5 7 \times \log_3 5)} \right) \)[/tex]. We'll start by looking at the term inside the logarithm.

### Step 1: Simplify [tex]\( \log_5 7 \times \log_3 5 \)[/tex]

We can use the change of base formula for logarithms, which says [tex]\( \log_b a = \frac{\log_c a}{\log_c b} \)[/tex]. Using this, we need to show that [tex]\( \log_5 7 \times \log_3 5 \)[/tex] simplifies to [tex]\( \log_3 7 \)[/tex]:

[tex]\[ \log_5 7 = \frac{\log 7}{\log 5} \][/tex]

[tex]\[ \log_3 5 = \frac{\log 5}{\log 3} \][/tex]

Multiplying these two results:

[tex]\[ \log_5 7 \times \log_3 5 = \left( \frac{\log 7}{\log 5} \right) \times \left( \frac{\log 5}{\log 3} \right) = \log_3 7 \][/tex]

So we have:

[tex]\[ E = 36^{\log_7 \left( 3^{\log_3 7} \right)} \][/tex]

### Step 2: Further simplify [tex]\( \log_7 \left( 3^{\log_3 7} \right) \)[/tex]

Notice that [tex]\( 3^{\log_3 7} \)[/tex] simplifies to 7 (since the base 3 raised to the power of [tex]\( \log_3 7 \)[/tex] essentially "cancels out" the logarithm):

[tex]\[ \log_7 (3^{\log_3 7}) = \log_7 (7) = 1 \][/tex]

This is because [tex]\( \log_b b = 1 \)[/tex] for any base [tex]\( b \)[/tex].

### Step 3: Substitute back and simplify:

Now we substitute back into our original expression:

[tex]\[ E = 36^1 = 36 \][/tex]

Thus, the reduced value of [tex]\( E \)[/tex] is:

C) 36