Answer
$\dfrac{24}{77}$
Work Step by Step
First, cancel out the common factors to obtain:
$\require{cancel}
\\=\dfrac{4\cancel{a}}{11\cancel{b}} \cdot \dfrac{6\cancel{b}}{7\cancel{a}}
\\=\dfrac{4}{11} \cdot \dfrac{6}{7}$
Multiply the numerators by each other and the denominators by each other to obtain:
$=\dfrac{24}{77}$