\[\left( 1\frac{2}{3}p + 2\frac{2}{5}q \right) =\]
\[= \left( \frac{5}{3}p + \frac{12}{5}q \right)^{2} =\]
\[= \frac{25}{9}p^{2} + 8pq + \frac{144}{25}q^{2} =\]
\[= 2\frac{7}{9}p^{2} + 8pq + 5\frac{19}{25}q²\]