Question

2.
The set of all natural numbers 'X' such that 3x + 7 < 28 is
A) {1, 2, 3, 4, 5, 6) B) infinite set
C) (0, 1, 2, 3, 4, 5, 6) D) {1, 2, 3, 4, 5, 6, 7}
​

Answer 1

a is correct option

if we place all digits 1 2 3 4 5 6 in place of x the answer will be less than 28

Answer 2

The set of all natural numbers 'X' such that 3x + 7 < 28 is {1, 2, 3, 4 , 5, 6}.

We have to find the set of all natural numbers ‘X’ such that 3x + 7 < 28.

What is set ?

In mathematics, “A set is a collection of well-defined objects or elements.”

A set can be represented in basically three forms. example of these are ..

1. Roaster form : A set of even number less than 10 = {2 , 4, 6 , 8}
2. Set builder form : A = {x : x = n², n ∈ N and 1 ≤ n ≤ 8 }
3. Statement form : it is just the statement of a set. if A = {1 , 2, 3 ...} , we say , A is set of all natural number.

Here , we have to find the set of all natural number such that 3x + 7 < 28

⇒3x + 7 < 28

⇒3x + 7 - 7 < 28 - 7

⇒3x < 21

⇒3x/3 < 21/3

⇒x < 7

so X is the set of all natural number less than 7.

i.e., X = {1, 2, 3, 4, 5 , 6}

hence option (A) is correct.