(√10+√5)√20-5√8 == √10 √20 + √5 √20 - 5 √8 == √(10 20) + √(5 20) - 5 √8 == √200 + √100 - 5 √8 == √(2 100) + 10 - 5 √(2 4) == √2 √100 + 10 - 5 2 * √4 == 10√2 + 10 - 10 == 10√2 + 0 == 10√2.
Ответ: 10√2.
(√10+√5)√20-5√8 =
= √10 √20 + √5 √20 - 5 √8 =
= √(10 20) + √(5 20) - 5 √8 =
= √200 + √100 - 5 √8 =
= √(2 100) + 10 - 5 √(2 4) =
= √2 √100 + 10 - 5 2 * √4 =
= 10√2 + 10 - 10 =
= 10√2 + 0 =
= 10√2.
Ответ: 10√2.