bonjour
f ( - 2 ) = 5 et f ( 2) = - 15
( - 15 - 5 ) / ( 2 + 2 ) = - 20 /4 = - 5
donc ax = - 5 x
f ( - 2 ) = 5
- 2 * - 5 + b = 5
10 + b = 5
b = 5 - 10 = -5
f (x) = - 5 x - 5
d'où f ( 2) = - 5 * 2 - 5 = - 10 - 5 = - 15
g ( 4 ) = - 1 et g ( ( 8 ) = - 2
( - 2 + 1 ) / ( 8 - 4 ) = - 1 /4
ax = - x / 4
g ( 4 ) = - 1
4 * - 1/4 + b = - 1
- 4/4 + b = - 1
b = - 1 + 1 = 0
g (x) = - x /4
g ( 8) = - 8 /4 = - 2
