Question

Aratati ca numarul a=√2(√18+√32--2√8).

Answer 1

$a= \sqrt{2} ( \sqrt{18} + \sqrt{32} -2 \sqrt{8})= \\ = \sqrt{36} + \sqrt{64} -2 \sqrt{16}= \\ =6+8-2*4= \\ =6.$

a=6=> a∈N.