Задача 19269 (sqrt(3)+sqrt(7))^2/(5+sqrt(21))...

u83139145236

09.11.2017

(sqrt(3)+sqrt(7))^2/(5+sqrt(21))

SOVA

09.11.2017

★

( sqrt(3)+sqrt(7))^2=(sqrt(3))^2+2*sqrt(3)*sqrt(7)+(sqrt(7))^2=
=3+2sqrt(21)+7=10+2sqrt(21)=2*(5+sqrt(21))

( sqrt(3)+sqrt(7))^2/(5+sqrt(21))=2*(5+sqrt(21))/(5+sqrt(21))=2