a)
34 = 3.54.5 = 1520
25 = 2.45.4 = 820
b)
1136
512 = 5.312.3 = 1536
c)
23 = 2.4.53.4.5 = 4060;
34 = 2.3.54.3.5 = 4560;
45 = 4.3.45.3.4 = 4860;