Thực hiện phép tính:

a)

 \[ = \frac{2}{3}.\frac{{ - 9}}{6} + \frac{1}{7}\]

 \( =  - 1 + \frac{1}{7}\)

 \( = \frac{{ - 6}}{7}\).

b)

 \( = \frac{{ - 3}}{{11}} \cdot \left( {\frac{5}{9} + \frac{4}{9}} \right)\)

 \( = \frac{{ - 3}}{{11}}.1\)

 \( = \frac{{ - 3}}{{11}}\).

c)

 \[ = \frac{{{{\left( {{3^2}} \right)}^5}.{{\left( {{2^3}} \right)}^2}}}{{{{\left( {{3^3}} \right)}^3}{{.2}^4}}}\]

 \[ = \frac{{{3^{10}}\,.\,{2^6}}}{{{3^9}\,.\,{2^4}}}\]

 \( = {3.2^2} = 3.4 = 12\).