When two rays are put together it forms an angle (because of the three points)
A set of ordered pairs, like the ones shown, represents a function only if each of the first coordinates is not repeated.
For example {(2, 5), (7, 8)} is a function, but {(2, 3), (6, 8), (2, -1)} is not because 2 is repeated.
We can check that each set of pairs we are given, are functions.
The inverses of each of these sets would be :
<span>{(–2, –1), (4, 0), (3, 1), (14, 5), (4, 7)} 4 repeats
{(2, -1), (4, 0), (5, 1), (4, 5), (2, 7)} 4 and 2 repeat
{(3, -1), (4, 0), (14, 1), (6, 5), (2, 7)} no repetition of 1st coordinates
{(4, -1), (4, 0), (2, 1), (3, 5), (1, 7)} 4 repeats
</span>
So only the inverse of <span>{(–1, 3), (0, 4), (1, 14), (5, 6), (7, 2)} is also a function</span>
