Which of the following relations is not a function?
A. {(7, 8), (8, 9), (9, 10), (7, 6)}
B. {(7, 8), (8, 9), (9, 10), (10, 11)}
C. {(7, 8), (8, 9), (9, 8), (10, 9)}
D. {(7, 8), (8, 8), (9, 8), (10, 8)}
when graphing do the straight line test on the x axis with a pencil or something and if the pencil touches more than one dot than it is not a function.
another way is to just look at the numbers for the x axis and if any of the numbers are the same for example (4,6), (4,9) then it is not a function. an example of a function would be (8,9), (2,6).
