1.Write 4+6+8+10 in sigma notation:

Question

I came up with sigma in the middle
3 on top
j=0 on the bottom
2n+4 to the right of the signma sign

2. Find the 10th term of the sequence
-1/5,-1/20,-1/80 this was a geometric sequence so I said a(subscript10) = -1/5*1/4^(10-1)
=-1/5*(1/4)^9 = -1/5*1/2621444
= -1/1310702