This is a geometric sequence with n th term formula
[tex]a_{n}[/tex] = [tex]a_{1}[/tex][tex](r)^{n-1}[/tex]
where r is the common ratio and [tex]a_{1}[/tex] the first term
here [tex]a_{1}[/tex] = - [tex]\frac{2}{3}[/tex] and
r = [tex]\frac{-144}{-24}[/tex] = [tex]\frac{-24}{-4}[/tex] = 6
[tex]a_{n}[/tex] = - [tex]\frac{2}{3}[/tex][tex](6)^{n-1}[/tex]
or in terms of x
f(x) = - [tex]\frac{2}{3}[/tex][tex](6)^{x-1}[/tex]
