√(㏒₂5+16㏒₅2-8)*㏒₅2+4㏒₅12,5 =√(1/(㏒₅2) +16㏒₅2-8)*㏒₅2+4㏒₅12,5 =
= √(1/(㏒₅2) *㏒₅2+16㏒₅2 *㏒₅2 - 8*㏒₅2)+4㏒₅12,5 =
=√(1+16 (㏒₅2)² -8*㏒₅2) + 4㏒₅ 12,5 = √(1-4㏒₅2)² + 4㏒₅12.5 =
=1 -4㏒₅2 + 4㏒₅12,5 = 1-4(㏒₅2+ ㏒₅12,5) =1 - 4(㏒₅2 * 12,5)=
=1- 4(㏒₅25) =1-4*2=1-8=-7