What does the partial sum equal?

Question

Answer 1

common ratio = 3

an = ar^(n-1)= -2(3^(n-1)= -1458

3^(n-1)= 729

3^3=27

27^2=729

3^6=729

n-1=6

n=7

a7=-1458

s7= a1(1-r ^7)/(1-3)

=-2(1-3^7)/-2

=1-3^7

=1-2187

=-2186