Réponses

  • Utilisateur Brainly
2013-05-11T09:56:49+02:00

on cherche a

a = f(x1) - f(x2) / x1 - x2

a = f(5) - f(8) / 5 - 8

a = - 4/3 - (-9) / 5 - 8

a = - 97/15

 

on cherche b

f(5) = - 4/3

a X 5 + b = -4/3

-97/15 X 5 + b = -4/3

- 97/3 + b = -4/3

b = -4/3 + 97/3

b = 31

 

f(x) = -97/15 x + 31