Bonjour,
1) f(x) = base + 50x
on sait que : f(10) = 1700
⇒ base + 50x10 = 1700 ⇒ base = 1700 - 500 = 1200
Donc : f(x) = 1200 + 50x
2) g(x) = 710 + 120x
3) f(x) = g(x)
⇔ 1200 + 50x = 710 + 120x
⇔ 120x - 50x = 1200 - 710
⇔ 70x = 490
⇔ x = 490/70 = 49/7 = 7
Le salaire vaut alors :
f(7) = 1200 + 50x7 = 1200 + 350 = 1550 €
ou
g(7) = 710 + 120x7 = 710 + 840 = 1550 €
