Question

1)

Answer 1

Answer:

X = {8n – 7n – 1 : n ϵ N}

Y = {49 (n –1) : n ϵ N} — (1) [all terms divisible by 49]

X = {8n – 7n – 1}

= (1 + 7)n – 7n – 1

= 1 + nC1 7 + nC2 72 + ….. + nCn 7n – 7n – 1

= nC2 72 + …… + nCn 7n

= 49 [nC2 + nC3 7 + …. nCn 7n-2] — (2)

From (1) and (2),

X is divisible by 49.

Y has all multiples of 49.

X ⊂ Y

Answer 2

Answer:

$to \: know \: the \: answer \:$

$refer \: to \: the \: above \: attatchment$

Hope this helps you XD ✌️

Carry on learning !!