How to simplify this arithmetic expression

Question

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.

Answer 1

Hint:

$$(\frac{3}{4})^6 = \frac{3^6}{4^6} $$

Answer 2

$[(3/4)^{7-4}]^2 \times 4^5 = [(3/4)^3]^2 \times 4^5 = (3/4)^6 \times 4^5 = (3^6)/(4^6) \times 4^5 = (3^6)/4 = 729/4$