(i) {1, 2, 3, …., 10} ≠ {x : x ∈ N and 1 < x < 10}

In R.H.S ‘x’ is than 1 and than 10 but L.H.S is having both 1 and .

(ii) {2, 4, 6, 8, 10} ≠ {x : x = 2n+1 and x ∈ N}

L.H.S ≠ R.H.S

R.H.S: x = 2n + 1 is definition of numbers.

L.H.S: Given set is numbers set.

(iii) {5, 15, 30, 45} ≠ {x : x is a multiple of 15}

x is a multiple of .

So does not exist.

(iv) {2, 3, 5, 7, 9} ≠ {x : x is a prime number}

x is a number but 9 is not a number.