let's firstly convert the mixed fractions to improper fractions and then multiply.
[tex]\bf \stackrel{mixed}{5\frac{3}{7}}\implies \cfrac{5\cdot 7+3}{7}\implies \stackrel{improper}{\cfrac{38}{7}}~\hfill \stackrel{mixed}{2\frac{2}{7}}\implies \cfrac{2\cdot 7+2}{7}\implies \stackrel{improper}{\cfrac{16}{7}} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{38}{7}\cdot \cfrac{16}{7}\implies \cfrac{(38)(16)}{(7)(7)}\implies \cfrac{604}{49}\implies 12\frac{20}{49}[/tex]
