Question

What are the coordinates of the centroid of a triangle with vertices A(-6, 0), B(-4, 4) and C(0, 2)

Answer 1

It turns out that the centroid of a triangle with given vertex coordinates is located at the mean of the three coordinates.
This can be validated by calculating the intersection of the medians.

So
Centroid=(-6-4+0, 0+4+2)/3=(-10/3,2)

Answer 2

Consider this long way.
Note, point O is the centroid of the triangle.