Answer:
This is geometric sequence.
[tex]n^{th} \ term \ in \ geometric \ sequence \ a_{n} = a_{1} \cdot r^{n-1}[/tex] ,
[tex]a_{1} \ is \ first \ term\\ r \ is \ the \ common \ divisor \\[/tex]
[tex]r = \frac{-48}{64} = \frac{3}{4}[/tex]
[tex]a_{7} = -64\ \cdot {\frac{3}{4} }^{7-1}\\\\a_{7} = -64\ \cdot {\frac{3}{4} }^{6}\\\\[/tex]= [tex]\frac{-64* 3*3*3*3*3*3}{4*4*4*4*4*4} = \frac{-729}{64}[/tex]