<s>[INST] How to simplify this arithmetic expression I'm trying to simplify:
$\left[(\frac{3}{4}\right)^{7}\cdot$  $\left(\frac{3}{4}\right)^{-4}]^{2}$ $\cdot4^5$ 
The only advance that I have done is
$\left[(\frac{3}{4}\right)^{14}\cdot$  $\left(\frac{3}{4}\right)^{-8}]$ $\cdot4^5$ 
and then $\left[(\frac{3}{4}\right)^{6}]$ $\cdot4^5$ 
the answer is$$\frac{3^6}{4}=\frac{729}{4}$$
I do not know what to do next, can someone please guide me in how to solve this exercise.
 [/INST] $[(3/4)^{7-4}]^2 \times 4^5 = [(3/4)^3]^2 \times 4^5 = (3/4)^6 \times 4^5 = (3^6)/(4^6) \times 4^5 = (3^6)/4 = 729/4$
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