Pls answer:

I suppose you want to say that E is any point on the median AD(D is the pointI have  assumed. It can be F,G,H,.. anything)

So then we have,

 A(triangle ABD)=A( triangle ACD)...(i).(as  a median of a triangle divides it into two triangles of equal area)

Simily,

A( triangle EBD)=A( triangle ECD)..(ii)

Subtracting  (ii) from(i)

we get the required result.