Question

Help!!!! I know the answer for #22 is -2730 but I don't know how to get it?

Answer 1

You are to sum 
-1 * 2^1
-1 * 2^3
-1 * 2^5
-1 * 2^7
-1 * 2^9
-1 * 2^11

which equals
-2
-8
-32
-128
-512
-2,048

which totals -2,730