Two vectors $\overrightarrow{A}$ and $\overrightarrow{B}$ lie in one plane, vector $\overrightarrow{C}$ lies in different plane. Then $\overrightarrow{A}+\overrightarrow{B}+\overrightarrow{C}$

Solution:

Two vectors $\overrightarrow{A}$ and $\overrightarrow{B}$ lie in one plane and vector $\overrightarrow{C}$ lies in different plane. Then $\overrightarrow{A}+\overrightarrow{B}+\overrightarrow{C}\ne 0$ i.e., always can't be zero.