Posted by Anonymous on Tuesday, February 21, 2012 at 2:02pm.
Point E is the centroid of triangle ABC. Find DB.
AF = 10x=3
EF = 2x+5
EB = 4x+3
This is for median of triangles.

geometry  Reiny, Tuesday, February 21, 2012 at 5:23pm
You have probably learned that the centroid divides a median in the ratio of 2:1, with the longer side towards the vertex.
I will assume that the median is AF, and you meant
AF = 10x + 3
so AF : EF = 2:1
(10x+3)/(2x+5) = 2/1
crossmultiply
10x + 3 = 4x + 10
6x = 7
x = 7/6
Not enough information to find DB.
Was the triangle isosceles or equilateral? 
geometry  Anonymous, Wednesday, February 22, 2012 at 3:05pm
Triangle is isosceles.