Which of the following functions is one-to-one?
Answer
a. {(2, 4), (3, 7), (-2, 1), (0, 5), (-1, 7)}
b. {(2, 1), (3, 6), (-2, 1), (0, 5), (-1, 7)}
c. {(2, 4), (3, 6), (-2, 1), (0, 5), (-1, 5)}
d. {(2, 4), (3, 6), (-2, 1), (0, 5), (-1, 7)}

Question

Which of the following functions is one-to-one?
Answer
	 a.	{(2, 4), (3, 7), (-2, 1), (0, 5), (-1, 7)}
	 b.	{(2, 1), (3, 6), (-2, 1), (0, 5), (-1, 7)}
	 c.	{(2, 4), (3, 6), (-2, 1), (0, 5), (-1, 5)}
	 d.	{(2, 4), (3, 6), (-2, 1), (0, 5), (-1, 7)}

anonymous · Answer

One to one means there is only 1 y for every x. If the same Y exists for a different X the function is NOT 1:1. (a) duplicates 7, (b) duplicates 1, (c) duplicates 5, The only function that has no duplicate Y values is d.