vector{DE}=-vector{AB}=-vector{p}
2)
vector{EF}=-vector{BC}=-vector{q}
3)
vector{AB}+vector{BC}+vector {CD}=vector{AD}
vector{AD}=2 vector{BC} =2 vector{q}
vector {CD}=vector{AD}-vector{AB}-vector{BC}=2 vector{BC} -vector{AB}-vector{BC}= vector{BC} -vector{AB}= vector{q} -vector{p}
4)
vector{FA}+vector{AB}+vector {BC}=vector{FC}
vector{FC}=2 vector{AB}=2 vector{p}
vector{FA}=vector{FC}-vector{AB}-vector {BC}=2 vector{AB}-vector{AB}-vector {BC}=vector{AB}-vector {BC}=vector{p}-vector {q}
vector {FA}=-vector {CD} можно и так
5)
vector{AD}=2 vector{BC} =2 vector{q}
6)
vector{AB}+vector{BC}=vector {AC}
vector {AC}=vector{p}+vector {q}