30) [sqrt(5)-sqrt(2)]^2 + 2sqrt(2)[sqrt(5)-sqrt(2)] =
5-2sqrt(10)+2+2sqrt(10)-2sqrt(10) = 7-2sqrt(10)
32) [3+2sqrt(2)]^2 - [3-sqrt(8)]^2 = 9+12sqrt(2)-[9-12sqrt(2)+8] =
9 + 12sqrt(2) - 9 + 12sqrt(2) - 8 = 24sqrt(2) - 8
38) 3 / [sqrt(5) + sqrt(2)] + 3 / [sqrt(8) + sqrt(5)] = 6 / {[sqrt(5) + sqrt(2)][sqrt(8) + sqrt(5)]} = 6 / [sqrt(40) + 5 + sqrt(16) + sqrt(10)] = 6 / [2sqrt(10) + 9 + sqrt(10)] = 6 / [3sqrt(10) + 9] = 6 * [3sqrt(10) - 9] / (90 - 81) = [6sqrt(10) - 18] / 3 = 2sqrt(10) - 6
Daca nu ai inteles undeva sau rezolvarea este gresita, te rog sa ma anunti.
