[tex]a_{6}[/tex] = - 3072
The n th term of a geometric sequence is
[tex]a_{n}[/tex] = [tex]a_{1}[/tex] [tex]r^{n-1}[/tex]
where [tex]a_{1}[/tex] is the first term and r the common ratio, hence
[tex]a_{6}[/tex] = 3 × [tex](-4)^{5}[/tex] = 3 × - 1024 = - 3072