(i) 54, 82
54)82(1x−54x2128)54(1x+1−28x2a+226)28(1x+1xa()−26x2a+2x+(2)26(13x+1xa++(−26x2a+2x+++0
Hence, HCF of 54 and 82 = 2.
(ii) 84, 120, 156
First, find HCF of 84 and 120:
84)120(1x)−84x21)36)84(2x+1(−72x2a+2(12)36(3x+1xa()−36x2a+2x+(0
So, HCF of 84 and 120 = 12.
Now, find HCF of 12 and 156:
12)156(13x)−156x21+)0
So, HCF of 12 and 156 = 12.
Hence, HCF of 84, 120 and 156 = 12.