Question

number of possible digit for X such that 198x 2 in divisible by 4

Answer 1

X may be 1, 3,5, 7 ,9.....

Answer 2

the divisibility rule of 4: of the last two digits of a number are divisible by for, the number is divisible by 4

let us take the last two numbers.
X2 .
12,32,52,72,92 are the numbers divisible by 4 with last digit 2.
so x can be 1,3,5,7, or 9

hope it helps