The numbers in the exponents just define how many times you have to multiply the same number by itself. Thus....
A
1. 6^8 is the same as:
6*6*6*6*6*6*6*6 ...which equals 1679616
2. 8^7 is the same as:
8*8*8*8*8*8*8 .....which equals 2097152
B
1. 20*20*20*20*20*20 is equivalent to: 20^6
2. 14*14*14*14*14 is equivalent to: 14^5