Answer:
Question 1: -2xy + 7x
Question 2: 8t - 4v and -4v + 8t
Question 3: -e + 10k and 10k -e
Question 4: x = -3
4w+x-4
Because when multiplying by a negative with a negative you will get a positive and multiplying a negative with a positive will get you a negative
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)
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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