Respuesta :

LanceLongFei

Answer:

-1310715

Step-by-step explanation:

By the formula of a geometric sequence, we work out:

[tex]\sum_{k=1}^{18} -5 \cdot 2^{k-1}\\= -5 \cdot \sum_{k=0}^{17} 2^{k}\\= -5 \cdot \frac{2^{18}-1}{2-1}\\= -1310715[/tex]