Answer:
13
Explanation:
From the sequence above the number has a negative sign,increasing and decreasing at rates not quite understandable unless a proper attention is paid.
The sequence of the above data is the reducing number by the specific value and the add double of same number in the outcome.
Take a look a this
-6-3 = -9(the first number is subtracted from the second)
12-(-6)=18
4 - 12 = -8
20 - 4 = 16
From the above one can realize that the outcome of every single linear algebra having the -ve sign will increase by 1(that means +1 is added to the previous number with a negative sign.
So to following the sequence, the next number will b -7
According to given pattern new number should be
x - 20 = -7
x = -7 +20
x = 13