Question

someone tell plz its in my exam

Answer 1

Answer:

First check for n=1 value=0; as 49 divides 0 and o is subset of y;now n>=2

Do binomial expansion of 8^N=(1+7)^n

Last 2 terms 7n+1 remaining each term is divisible by 49;

So each value of x Is divisible by 49;

but some multiple of 49 are missing in x example 78

So x is subset of y