Are the following pair of sets equal? Give reasons.

(i) A = {2, 3}; B = {x: x is solution of x² + 5x + 6 = 0}

x² + 5x + 6 = 0 can be written as

x(x + 3) + 2(x + 3) = 0

By further calculation

(x + 2) (x + 3) = 0

So we get

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}

Order in which the elements of a set which are listed is not significant.

Therefore, A = B.