√27 + √12 - √75 =
= 3√3 + 2√3 - 5√3
= 5√3 - 5√3
= 0
[(√3 - 1)/√3 + (√5-√3)/√15 + (√7-√5)/√35 + (√9-√7)/√63]×(1/√3)⁻² =
= [(√3-1)√3/3 + (√5-√3)√15/15 + (√7-√5)√35/35 + (3-√7)/3√7]×(√3)²
= [(3-√3)/3 + (√75-√45)/15 + (√245-√175)/35 + (3√7-7)/21]×3
= 3(3-√3)/3 + 3(5√3-3√5)/15 + 3(7√5-5√7)35 + 3(3√7-7)/21
= ³⁵⁾3 - √3 + ⁷⁾(5√3 - 3√5)/5 + (21√5-15√7)/35 + ⁵⁾(3√7-7)/7
= (105 - 35√3 + 35√3 - 21√5 + 21√5 - 15√7 + 15√7 - 35)/35
= (105 - 35)/35
= 70/35
= 2
