Bonjour, pourriez m’aider pour l’exercice 3 Merci

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

x = - 5