(3√6)²/18 = (9*6)/18 = 54/18 = 3
√200/4√2 = √(2*10²)/4√2 = 10√2/4√2 = 10/4 = 5/2
√(45*27) * √60 = √(5*9*3³) * √(4*15) = √(15*3⁴)*√(2²*15) = 3²√15 * 2*√15 = 18*15 = 270
√72 + √8 - 8√2 + 2 = √2*6² + √2²*2 - 8√2 + 2 = 6√2 + 2√2 - 8√2 + 2 = 2
(√10 - √6)(√10 + √6) = √10² - √6² = 10 - 6 = 4