Çözüldü Centroid of a Triangle

If a triangle's vertices are A(3, 4), B(-3, 2), C(x, y) and its centroid is on the line 3x + 3y - 8 = 0 what is the sum of the coordinates of the vertex C?
https://i.ibb.co/GHB6Rf4/triangle-centroid.png
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The coordinates of the centroid: G[ (3 - 3 + x) / 3, (4 + 2 + y) / 3 ]
G(x / 3, 2 + y / 3)....(I)
Now that centroid is on the line given in the question, substituting the coordinates on its equation;
3(x / 3) + 3(2 + y / 3) - 8 = 0
x + 6 + y - 8 = 0
x + y = 2

Reference: https://www.mathopenref.com/coordcentroid.html