You need to refer to your text for an understanding of their meaning of "all the equivalents".
1. There are an infinite number of equivalents to 5^-3. You have shown one of them. Another is 1/125.
2. Likewise for 2^-4 = 1/2^4 = 1/16.
3. There are an infinite number of equivalents to 4^2 = 16. You have shown only 2 of them.
4. There are an infinite number of equivalents to 3^7 = 3*3^6 = 9*3^5 = 27*3^4 = 3*27^2 = 3*9^3 = 2187 = 4374/2 = ...
5. There are an infinite number of equivalents to 3^2*3^-2 = 3^0 = 1.
6a. 4^-3/4^2 = 4^(-3-2) = 4^-5 = 1/4^5 = 1/2^10 = 1/1024
6b. 2^5/2^-3 = 2^(5 -(-3)) = 2^8 = 4^4 = 16^2 = 256
6c. 3^7/3^2 = 3^(7 -2) = 3^5 = 243
7. 2,000,000*2^(2010-2005) = 2,000,000*2^5 = 32*2,000,000 = 64,000,000
