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.

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?

Triangle is isosceles.

To find the length of DB, we need to use the concept of the centroid of a triangle. The centroid divides each median into two segments: one that is twice as long as the other. Since point E is the centroid of triangle ABC, we can use this information to solve for the length of DB.

Let's first denote the length of DB as y. According to the concept of the centroid, DE will be twice as long as EB. So, we have:

DE = 2 * EB
DE = 2 * (4x + 3)
DE = 8x + 6

Furthermore, AE will be twice as long as EF. So, we have:

AE = 2 * EF
AE = 2 * (2x + 5)
AE = 4x + 10

Now, using the concept that the centroid divides each median into two segments, we can write:

AD = 2 * DB
AD = 2 * y

Also, AD = AE + DE. Substituting the values we found earlier, we have:

4x + 10 + 8x + 6 = 2y
12x + 16 = 2y

To solve for y, we need to isolate y. Divide both sides of the equation by 2:

6x + 8 = y

Therefore, the length of DB, or y, is 6x + 8.