If A × B = {(1, 3), (1, 4), (2, 3), (2, 4), (3, 3), (3, 4)}

Then,

A = Set of first elements = {1, 2, 3}

B = Set of second element = {3, 4}

Let us check

If A = {1, 2, 3}, B = {3, 4}

A × B = {(1, 3), (1, 4),

(2, 3), (2, 4),

(3, 3), (3, 4)}

Which is the same as above.