Explanation:
(5^-3)^6 = 5^(-3 * 6 ) = 5^(-18)
5^(-18) * 5^17 = 5^(-18+17) = 5 ^-1
put 5 ^-1 in the denominator ....this changes it to 5^(+1) ....or just '5'
move 10^-2 to the numerator to change it to 10^2 ...or just 100
then you are left with 10^2 / 5 = 100 / 5 = 20