57. As shown in the figure, points $D, E$ are on the sides $A C, A B$ of $\triangle A B C$ respectively, and the line $B D$ intersects $C E$ at point $F$. It is known that the areas of $\triangle C D F, \triangle B F E, \triangle B C F$ are 3, 4, 5 respectively. Then the area of quadrilateral $A E F D$ is $\qquad$ .
Answer: $\frac{204}{13}$