A and im typing more for charater limit
The value for n is 
<h3>solving for n</h3>
<u>given data</u>
10n^{2} - 12 = -8
making n the subject of the formula
10n^{2} = -8 + 12
10n^{2} = 4
divide through by 10
n^{2} = 4 / 10
finding the square root of both sides
n = square root ( 4 / 10 )

n = 0.632 or 
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Answer:
Step-by-step explanation:
a = 5
r = -5
n = 9
t_9 = a r^(n - 1)
t_9 = (-1)^n*5 (-5) ^ 8
t_9 = (-1)^9 * 5 * (-5) ^8
t_9 = -1 ( 1953125)
t_9 = - 1953125