\[\boxed{\mathbf{589\ (589)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[S_{\text{ABCD}} = 16\ см^{2}.\]
\[S_{\text{ACFE}} = S_{\text{ACD}} + S_{\text{CFD}} + S_{\text{ADE}}\]
\[S_{\text{ACD}} = 16\ :2 = 8\ см^{2}.\]
\[S_{\text{CFD}} = S_{\text{ADE}} = 8\ :2 = 4\ см^{2}.\]
\[S_{\text{ACFE}} = 8 + 4 + 4 = 16\ см^{2}.\]
\[Ответ:16\ см^{2}\text{.\ }\]
\[\boxed{\mathbf{589}.\ }\]
\[1)\ 3a + 1;\]
\[2)\ 8a + 3.\]