We know that the value x we are looking for is even, and is greater than 6 and less than 10.
We start with the condition of being even.
Then x can be 2, 4, 6, 8, 10, 12, 14...
If we know that is greater than 6, we can eliminate 2, 4 and 6 from the list.
x can be: 8, 10, 12, 14...
If we know that x is less than 10, we can eliminate 10 and all the values above 10.
Then, x is 8, as it is the only value left in the list of possible values.
Answer: the number is 8.