Answer :
The formula to use for the sum of n terms is as follows:
[tex]S_{n}=\frac{a(1-r^{n})}{1-r}[/tex]
r = -3, n = 6.
[tex]S_{6}=\frac{4(1-(-3)^{6})}{1-(-3)}=-728[/tex]
[tex]S_{n}=\frac{a(1-r^{n})}{1-r}[/tex]
r = -3, n = 6.
[tex]S_{6}=\frac{4(1-(-3)^{6})}{1-(-3)}=-728[/tex]