) (√6 + √3)√12 - 2√6 * √3 = √72 + √36 - 2√18 = 6√2 + 6 - 2 * 3√2 =
= 6√2 + 6 - 6√2 = 6
2) (√10 + √5)√20 - 5√8 = √200 + √100 - 5√8 = 10√2 + 10 - 5 * 2√2 =
= 10√2 + 10 - 10√2 = 10
3) (√15 + √5)√15 - 5/3√27 = √(15)² + √75 - 5/3√(9*3) =
= 15 + √(25*3) - 5/3 * 3 *√3 = 15 + 5√3 - 5√3 = 15
4) (√18 + √3)√2 - 0,5√24 = √36 + √6 - 0,5√(4 * 6) =
= 6 + √6 - 0,5 * 2 * √6 = 6 + √6 - √6 = 6