Решение
1) (7 + √7)/3√7 = [(7 + √7)*√7] /[3√7*√7] = (7√7 + 7) / 21 = (√7 + 1) / 3
2) (c² - 2)/(c - √2) = [c - (√2)²] / (c - √2) = [(c - √2) * (c + √2)] / (c - √2) =
= c + √2
3) 12/7√6 = (12*√6) / (7*√6*√6) = (12√6)/(7 * 6) = 2√6/7
4) 5 / (√13 + √3) = [5* (√13 - √3)] / [ (√13 + √3) * (√13 - √3)] =
= [5* (√13 - √3)] / (13 - 3) = [5* (√13 - √3)] / 10 = (√13 - √3) / 2