Answer:
[tex]\displaystyle \text{series}=\sum_{n=0}^{\infty}{5\cdot(-2)^n}[/tex]
Step-by-step explanation:
The first term is 5 and the common ratio is -2. The general term for n starting at 1 can be written as ...
an = a1·r^(n-1)
If we start n at 0, then we can eliminate the -1 from the exponent:
[tex]\displaystyle \text{series}=\sum_{n=0}^{\infty}{5\cdot(-2)^n}[/tex]