а) 7/√21 = 7/(√(37)) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(3√7) = 7/(3√7) = (7√7)/(3*7) = √7/3
б) 7/(√12+√5) = 7/(√(43)+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = (7(2√3-√5))/(2√3+√5)(2√3-√5)) = (14√3-7√5)/(43-5) = (14√3-7√5)/(12-5) = (14√3-7√5)/(7) = 2√3-√5
а) 7/√21 = 7/(√(37)) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(√3 √7) = 7/(3√7) = 7/(3√7) = (7√7)/(3*7) = √7/3
б) 7/(√12+√5) = 7/(√(43)+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = 7/(2√3+√5) = (7(2√3-√5))/(2√3+√5)(2√3-√5)) = (14√3-7√5)/(43-5) = (14√3-7√5)/(12-5) = (14√3-7√5)/(7) = 2√3-√5