Répondre :
(5-√5) (3+2√5) (2-√5) - (1-2√5)
=(15+10√5-3√5-2*5)(2-√5)-(1-2√5)
=(5+7√5)(2-√5)-1+2√5
=10-5√5+14√5-7*5-1+2√5
=-25+9√5-1+2√5
=-26+11√5
(5-√5) (3+2√5) (2-√5) - (1-2√5)
=(15+10√5-3√5-2*5)(2-√5)-(1-2√5)
=(5+7√5)(2-√5)-1+2√5
=10-5√5+14√5-7*5-1+2√5
=-25+9√5-1+2√5
=-26+11√5