Answer
$\dfrac{1}{12}$
Work Step by Step
Simplify within each group by making the fractions similar using their LCD to obtain:
\begin{align*}
\require{cancel}
&=\left[-\frac{4}{7}+\frac{2}{5}\right]\left[-\frac{3(9)}{8(9)}+\left(-\frac{1(8)}{9(8)}\right)\right]\\\\
&=\left[-\frac{4(5)}{7(5)}+\frac{2(7)}{5(7)}\right]\left[-\frac{27}{72}+\left(-\frac{8}{72}\right)\right]\\\\
&=\left[-\frac{20}{35}+\frac{14}{35}\right]\left[-\frac{27+8}{72}\right]\\\\
&=\left[\frac{-20+14}{35}\right]\left[-\frac{35}{72}\right]\\\\
&=\left[\frac{-6}{35}\right]\left[-\frac{35}{72}\right]\\\\
&=\left[\frac{-\cancel{6}}{\cancel{35}}\right]\left[-\frac{\cancel{35}}{\cancel{72}12}\right]\\\\
&=\frac{1}{12}
\end{align*}
