Bonsoir
f (x) = 2.4 x
A ( 8/6 ) = 2.4 x 8/6 = 19.2/6 donc A ∉ C
B ( - 3/6 ) = 2.4 x - 3/6 = - 7.2/6 donc B ∉ C
C ( 1.5 ) = 2.4 x 1.5 = 3.6 donc C ∈ C
D ( - 2.6 ) = 2.4 x - 2.6 = - 6.24 donc D ∉ C
f ( - 5 ) = 2.4 x - 5 = - 12
2.4 x = 9
x = 3.75
abscisse = 3.75