Solution:
First, determine the 1st term
[tex]A_n=A_1(r)^{n-1}\\\\3,125=A_1(-5)^{5-1}\\\\3,125=A_1(-5)^4\\\\3,125=A_1(625)\\\\\frac{3,125}{625}=A_1\\\\A_1=5[/tex]
Therefore:
[tex]A_1=5\\A_2=5(-5)=-25\\A_3=-25(-5)=125\\A_4=125(-5)=-625\\A_5=-625(-5)=3,125\\A_6=3125(-5)=-15,625\\[/tex]
and so on...
[correct me if I'm wrong]
