Question

The sets A=(1,2,3) and B=[X&R:X-2X+1=0) are equal or not? Justify your answer.​

Answer 1

Two set A & B are equal if every element of A is the element of B and every element of B is the element of A. Example: {1,2,3,4} and {3,4,2,1} are equal.

A = {1, 2, 3}

Now check each element of set A in the value of x

B = [x ∈ R : x - 2x + 1 = 0]

Putting x = 1, we get,

1 - 2 + 1 = 0

0 = 0 ✓

Putting x = 2, we get,

2 - 4 + 1 = 0

-1 ≠ 0 X

As, 2 is not element of B ,

Set A ≠ Set B