Answer:
Step-by-step explanation:
[tex]a(n)=-5\cdot2^{n-1}\\\\\text{put n = 1, n = 4 and n = 8 to the expression:}\\\\a(1)=-5\cdot2^{1-1}=-5\cdot2^0=-5\cdot1=-5\\\\a(4)=-5\cdot2^{4-1}=-5\cdot2^3=-5\cdot8=-40\\\\a(8)=-5\cdot2^{8-1}=-5\cdot2^7=-5\cdot128=-640[/tex]
