bonjour,
f (x) = x² + 3 x - 7
x² + 3 x - 7 = - 7
x² + 3 x = - 7 + 7
x² + 3 x = 0
1 ) f (0) = - 7
2 ) f ( 6) = 36 + 18 - 7 = 47
3 ) h ( - 2 ) = 9 et h ( 0) = 5
( 5 - 9 ) / ( 0 + 2 ) = - 4/2 = - 2
la fonction est de type ax + b
ax = - 2 x
f ( - 2 ) = 9
- 2 * - 2 + b = 9
b = 9 - 4 = 5
h (x) = - 2 x + 5
d'où h ( 0) = 0 + 5 = 5