√72·(2√18-5√72-7√128+9√450)=
=6√2·(6√2-30√2-56√2+135√2)=
=6√2·55√2=660
18(√3-2√2)+15(2√3-3√2)-7(3√3-√2)=
=18√3-36√2+30√3-45√2-21√3+7√2=
=27√3-74√2
5√5-3(√15+2)+4(1-√15)=
=5√5-3√15-6+4-4√15)=
=5√5-7√15-2
√7(√3-2√8)+5√56-√84=
=√21-4√14+10√14-2√21=
=6√14-√21=
=√7(6√2-√3)
√3(√2-2√5)+√60-√24=
=√6-2√15+2√15-2√6=
=-√6