Question

Помогите пожалуйста!
Вычислите:

Answer 1

$frac{20}{7- sqrt{29} } - frac{15}{6+ sqrt{21} } - frac{8}{ sqrt{29}- sqrt{21} } =\ frac{20(7+ sqrt{29})}{(7- sqrt{29})(7+sqrt{29}) } - frac{15(6- sqrt{21})}{(6+ sqrt{21})(6- sqrt{21}) } - frac{8(sqrt{29}+ sqrt{21})}{( sqrt{29}- sqrt{21})(sqrt{29}+ sqrt{21}) } =\ frac{20(7+ sqrt{29})}{49-29 }- frac{15(6- sqrt{21})}{36-21 }-frac{8(sqrt{29}+ sqrt{21})}{29-21}=\ 7+ sqrt{29} -6+ sqrt{21} - sqrt{29}- sqrt{21} =1$