Question

(√28 -2 √14 + √7) √7 +7 √ 8

Answer 1

\(\left(\sqrt{28}-2\sqrt{14}+\sqrt{7}\right)\cdot\sqrt{7}+7\sqrt{8}\)

\(=\left(3\sqrt{7}-2\sqrt{14}\right)\cdot\sqrt{7}+14\sqrt{2}\)

\(=21\)

Answer 2

( ^28 - 2^14 +^7 ) ^ 7 + 7^8 

= ( ^ 4.7 - 2^14 + ^7 ) ^7 + 7^4.2

= ( 2^7 - 2^14 + ^7 ) ^7 + 7.2^2

= ( 3^7 - 2^14 ) ^7 + 14^2

= 21 - 14^2 + 14^2

= 21