Answer:
a17=3
Step-by-step explanation:
an=a1+(n−1)d geometric sequence formula
-2=a1+(18-1)(-5)
-2=a1+17(-5)
-2=a1-85
a1=83
a17=83+(17-1)(-5)
a17=83+16(-5)
a17=83-80
Hope this helps! Please mark brainliest :)