Réponse :
f(-1/4) = - 11/4
f(1/7) = 11/7
ax + b
-1/4a + b = - 11/4 b = - 11/4 + 1/4a
1/7a + (-11/4 + 1/4a) = 11/7 (4*1)/(4*7a) + (7*1)/(7*4) = 11/7 - 1/7
4/28a + 7/28a = 10/7 11/28a = 10/7 a = 10/7 * 28/11 = 280/77
b = - 11/4 + 1/4 (280/77) = - 11/4 + 280/308 = - 11/4 + 10/11 = (-11*11)/(4*11) + (10*4)/(11*4) = 121/44 + 40/44 = 162/44 = 81/22
Explications étape par étape :
