(i) A = {2, 3}; B = {x: x is solution of $x^{2}+5x+6=0$}
$x^{2}+5x+6=0$ can be re-arranged as
x(x + 3) + 2(x + 3) = 0
(x + 2) (x + 3) = 0
So,
x = –2 or x = –3
Here
A = {2, 3}; B = {–2, –3}
Therefore, A ≠ B
(ii) A = {x: x is a letter in the word FOLLOW} = {F, O, L, W}
B = {y: y is a letter in the word WOLF} = {W, O, L, F}
The order in which the items of a set are listed has no significance.
As a result, $A = B$