Question

(корень7-корень28)^2

Answer 1

Формула: (a-b)^2=a^2-2ab+b^2
(√7-√28)^2=(√7)^2-2*√7√28+(√28)^2=7-2√7*28+28=35-2√7*7*4=35-2*7*2=35-28=7