Your sequence appears to be geometric with a common ratio of 2. It can be described by
a(n) = (-2 2/3)·2^(n-1)
_____
This can be written in a number of other forms, including
a(n) = (-8/3)·2^(n-1)
a(n) = (-1/3)·2^(n+2)
a(n) = (-4/3)·2^n
1 foot = 12 inches, so now you add 3 inches until you get 12. you add 3, 4 times toget 12. 3+3=6+3=9+3=12 and do that again for the 2nd foot 3+3=6+3=9+3=12 you added 3, 4 times to get 12 twice so now add 4+4=8
YOUR ANSWER IS 8
3*4=12
8*4=32
It is a ratio.
PERIODDDDDDDSDDDDDDDDDDDDDD
-10 + a = 6a - 7a
Rearrange the left hand side
a - 10 = 6a - 7a
Simplify 6a - 7a
a - 10 = -a
Add a on both sides
2a - 10 = 0
Add 10 on both sides
2a = 10
Divide by 2 on both sides
a = 5