Which of the sets of ordered pairs represents a function?

A = {(1, −5), (8, −5), (8, 7), (2, 9)}
B = {(7, −4), (7, −2), (6, −3), (−9, 5)}

Only A
Only B
Both A and B
Neither A nor B

Question

Which of the sets of ordered pairs represents a function?

A = {(1, −5), (8, −5), (8, 7), (2, 9)}
B = {(7, −4), (7, −2), (6, −3), (−9, 5)}

 Only A
 Only B
 Both A and B
 Neither A nor B

triciaal · Answer

you have a function when there is only one y-value for a given x-value 
only one output for any one input

soahelp · Answer

so the answer would be Both A and B

rhystic · Answer

so if you look at the coordinate sets, a function is either linear or nonlinear. Non linear functions will never have two points lieing in a straight line it will always be offset even by a decimal point. In those two coordinate sets there is a pair that lie on the same line while the others do not... that is not a function.

triciaal · Answer

no, it would be neither A nor B 
A cannot be a function because input 8 has 2 outputs -5 and 7
B cannot be a function because input 7 has 2 outputs -4 and -2

soahelp · Answer

oh okay thxs for your help

triciaal · Answer

read my definition again in order to be a function you cannot have 2 outputs for the same input

triciaal · Answer

welcome