Which sets of points represent one-to-one functions?
f = {(1,2), (2,3), (3,4),(4,5), (5,6), (6,7), (7,8), (8,8)}
g= {(1,2), (3,3), (5,4), (7,4), (9,4), (11,4), (13,4), (17,4)}
I h = {(1,6), (2,3), (3,16), (4,21), (5,27), (6,36), (7,48), (8,56)}
i = {(0,1), (1,3), (3,5), (5,3), (7,4), (9,6), (11,9), (13,10)}
j = {(2,6), (4,16), (6,26), (8,36), (10,16), (12,56), (14,66), (16,16);
k = {(2,6), (4,16), (6,26), (8,36), (10,46), (12,56), (14,66), (16,76)}