bonsoir
f (x) = 5 - 3 x
f (0) = 5
f ( 1) = 5 - 3 = 2
f ( - 2 ) = 5 + 6 = 11
antécédents
5 - 3 x = - 1
- 3 x = - 1 - 5
- 3 x = - 6
x = 2
5 - 3 x = 14
- 3 x = 14 - 5
- 3 x = 9
x = - 3
5 - 3 x = 0
- 3 x = - 5
x = 5/3