Equal Sets = Two sets A and B are said to be equal if they have exactly the same elements & we write A = B

We have, 

E = {x : x ϵ Z, x² ≤ 4}

Here, x ∈ Z and x² ≤ 4 

If x = -2, then x² = (-2)² = 4 = 4 

If x = -1, then x² = (-1)² = 1 < 4 

If x = 0, then x² = (0)² = 0 < 4 

If x = 1, then x² = (1)² = 1 < 4 

If x = 2, then x² = (2)² = 4 = 4 

So, 

E = {-2, -1, 0, 1, 2} 

and F = {x : x ϵ Z, x² = 4} 

Here, x ∈ Z and x² = 4 

If x = -2, then x² = (-2)² = 4 = 4 

If x = 2, then x² = (2)² = 4 = 4 

So, F = {-2, 2} 

∴ E ≠ F because the elements in the both the sets are not equal.