Question

√69-16√5
Все под корнем

Answer 1

$sqrt{69-16 sqrt{5} } = sqrt{64-16 sqrt{5}+5 } = sqrt{8^{2}-2*8* sqrt{5} +( sqrt{5})^{2} } = \ \ = sqrt{(8- sqrt{5})^{2} } =8- sqrt{5} .$