(2-√3)∙√(7+4√3) =
(2-√3)∙√(4+4√3+3) =
(2-√3)∙√(2^2+4√3+√3^2) =
(2-√3)∙√(2+√3)^2 =
(2-√3)∙(2+√3)=
2^2 -√3^2=
4-3=1
(2-√3)∙√(7+4√3) = (2-√3)∙√(2+√3)(2+√3) =(2-√3)(2+√3)=1
