For a number to be divisible by 8, its last 3 digits should be divisible by 8. In this case, 6x8 should be divisible by 8.

When we substitute x with digits from 0 to 9, we get 608, 618, 628... till 698. Now, 608 is divisible by 8. Also 648 and 688 are divisible by 8. No other number other than these 3 is divisible by 8. So x can take 3 different values- 0, 4 and 8.