Answer :
Answer: A
Step-by-step explanation:
[tex]A_n=9+(n-1)*(-4)\\\\A_1=9+(1-1)*(-1)=9+0=9\\\\A_{n-1}=9+((n-1)-1)*(-4)\\\\A_n-A_{n-1}=9+(n-1)*(-4)-(9+(n-2)*(-4))=-4n+4+4n-8=-4\\\\\boxed{A_n=A_{n-1}-4}\\\\\\Answer\ A[/tex]
Answer: A
Step-by-step explanation:
[tex]A_n=9+(n-1)*(-4)\\\\A_1=9+(1-1)*(-1)=9+0=9\\\\A_{n-1}=9+((n-1)-1)*(-4)\\\\A_n-A_{n-1}=9+(n-1)*(-4)-(9+(n-2)*(-4))=-4n+4+4n-8=-4\\\\\boxed{A_n=A_{n-1}-4}\\\\\\Answer\ A[/tex]