The geometric sequence
4, -20, 100, …
The formula for the general term
for each geometric sequence is...
an = a1r^(n - 1)
a1 = 4
r = -5
a8 = 4*(-5)^7 = -312,500
ur first number of the jeometric sequence is 4 so a=4
als ur q (the multiple part im not good in eng sorry) q=-5 cuse
-20/4=q=-5 or 100/-20=q=-5 any way q=-5 is obvious in the sequence
the 8th term is a*q^7 (its obvious too)
so the 8th term lets call it x
x=4*(-5)^7=4*(-9765625)=-39062500
sorry for my eng again hope to be helpful
-312500
multiply by (-5) every time, if you do that until the 8th term you get -312500
4, -20, 100, -500, 2500, -12500, 85000, -425000
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Verified answer
The geometric sequence
4, -20, 100, …
The formula for the general term
for each geometric sequence is...
an = a1r^(n - 1)
a1 = 4
r = -5
a8 = 4*(-5)^7 = -312,500
ur first number of the jeometric sequence is 4 so a=4
als ur q (the multiple part im not good in eng sorry) q=-5 cuse
-20/4=q=-5 or 100/-20=q=-5 any way q=-5 is obvious in the sequence
the 8th term is a*q^7 (its obvious too)
so the 8th term lets call it x
x=4*(-5)^7=4*(-9765625)=-39062500
sorry for my eng again hope to be helpful
-312500
multiply by (-5) every time, if you do that until the 8th term you get -312500
4, -20, 100, -500, 2500, -12500, 85000, -425000