Question

корень125+2*корень80-2*корень45+3*корень20)корень5

Answer 1

$(sqrt{125}+2sqrt{80}-2sqrt{45}+3sqrt{20})* sqrt{5}=\ (sqrt{125}+sqrt{320}-sqrt{180}+sqrt{180})*sqrt{5}= \ = (sqrt{125}+sqrt{320})* sqrt{5}= \ (sqrt{5}*sqrt{25}+sqrt{5}*sqrt{64})* sqrt{5}=(5sqrt{5}+8sqrt{5})*sqrt{5}= \ sqrt{5}(5+8)*sqrt{5}=5*13=65$

Answer 2

$(sqrt{125}+2sqrt{80}-2sqrt{45}+3sqrt{20})*sqrt{5}=sqrt{125*5}+2sqrt{80*5}-\\-2sqrt{45*5}+3sqrt{20*5}=sqrt{625}+2sqrt{400}-2sqrt{225}+3sqrt{100}= \\=25+2*20-2*15+3*10=25+40-30+30=65$