Question

if A,B and C vector not in the same plane is it possible to get A+B+C=0

Answer 1

Nope, this is what we call a set of linearly independent vectors. The reason why is simple actually. Imagine you are a little ant on the desk. So you can move left and right or forwards and backwards. But you don't have wings so you can't move up out of the plane of the desk! No amount of moving on the desk will ever get you to a point above the desk.

Similarly in just 2 dimensions no amount of left-right movement will ever get you to another point off of that line.