bonjour
f (x) = 2 x
f ( 3) = 3*2 = 6
2 x = 8
x = 4
g (x) = 3 x
g ( - 4) = - 4 *3 = - 12
3 x = - 15
x = - 5
f (x) = 5 x
f ( 3) = 15
5 x = - 15
x = - 3
h (x) = - 7 x
h ( - 2 ) = 14
- 7 x = 35