=7vector{p}×vector{p}-2vector{q}×vector{p}+21vector{p}×vector{q}-6vector{q}×vector{q}=
так как
vector{p}×vector{p}=vector{q}×vector{q}=0,
vector{p}×vector{q}=-vector{q}×vector{p}, то
=23vector{p}×vector{q}
S=|vector{a}×vector{b}|=|23vector{p}×vector{q}|=
=23*|vector{p}|*|vector{q}|*sin ( vector{p},vector{q})=
=23*(1/2)*2*1=23
О т в е т. 23