Réponse :
bonjour
coefficient = - 2/3
f (x) = 0.3 x
coefficient = 4
f ( x) = 5 x /4
60 * 0.7 = 42
pantalon = 42 €
0.7 x = 21
x = 30
prix avant soldes = 30
f (x) = - 3 x
f ( 5 ) = - 15
f ( - 2 ) = 6
- 3 x = - 12
x = 4
- 3 x = 8
x = - 8/3
Explications étape par étape :