Problems based on Numbers Test 3

As per the divisibility rule of 3, if the sum of all the digits is divisible by 3, then the number is also divisible by 3.
3 + 7 + 9 + 1 + 7 + 2 + 5 + 6 + 4 + x + 8 must also be divisible by 3
⇒ 52 + x
52 + 8 = 60 and 60 is divisible by 3.
So, the largest possible value of x = 8.