√5 ⋅ 18 ⋅ √10 = 18 ⋅ √(5 ⋅ 10) = 18 ⋅ √(5 ⋅ 5 ⋅ 2) = 18 ⋅ 5 ⋅ √2 = 90√2
4√34 - 3√2 ⋅ √17 = 4√(2⋅17) - 3√2 ⋅ √17 = 4√2 ⋅ √17 - 3√2 ⋅ √17 = √2 ⋅ √17 (4 - 3) = √2 ⋅ √17 = √34
√13 ⋅ √65 / √5 = √(13 ⋅ 65) / √5 = √(13 ⋅ 13 ⋅ 5) / √5 = 13 ⋅ √5 / √5 = 13
(√27 + √3) ⋅ √3 = (√(9 ⋅ 3) + √3) ⋅ √3 = (3√3 + √3) ⋅ √3 = 4√3 ⋅ √3 = 4 ⋅ 3 = 12
(√5 + √7)(√5 - √7) = (√5)2 - (√7)2 = 5 - 7 = -2
Ответ: 1) 90√2; 3) √34; 5) 13; 7) 12; 9) -2