Question

Which function has an inverse that is also a function?
{(–1, –2), (0, 4), (1, 3), (5, 14), (7, 4)}
{(–1, 2), (0, 4), (1, 5), (5, 4), (7, 2)}
{(–1, 3), (0, 4), (1, 14), (5, 6), (7, 2)}
{(–1, 4), (0, 4), (1, 2), (5, 3), (7, 1)}

Answer 1

The third set: {(–1, 3), (0, 4), (1, 14), (5, 6), (7, 2)}.

Reason: its output values (3,4,14,6,2) are all distinct, so the relation is one-to-one and its inverse is a function.