The geometric sequence is given by the next formula:
[tex]a_n=a_1(r)^{n-1}[/tex]
Where r represents the common ratio and n is the number for the sequence.
Now, we have the next given values:
r=-2
a1 =4
and we need to find a7, which means n=7.
Replacing on the geometric sequence formula:
[tex]a_7=-4(-2)^{7-1}[/tex][tex]a_7=-4(-2)^6[/tex][tex]a_7=-256[/tex]
Then, the correct answer is option C.
