Sagot :
bonjour
f (5) = 10 et f ( 10 ) = 11
( 11 - 10 ) / ( 10 - 5) = 1/5 donc ax = x /5
f ( 5) = 10
5 * 1/5 + b = 10
b = 10 - 5/5 = 10 - 1 = 9
f (x) = x /5 + 9
d'où f ( 10 ) = 10/5 + 9 = 2 + 9 = 11
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f ( - 7 ) = 4 et f ( 4) = - 7
( - 7 - 4 ) / ( 4 + 7 ) = - 11 /11 = - 1 donc ax = - x
f ( - 7) = 4
- 7 * - 1 + b = 4
b = 4 - 7 = - 3
f (x) = - x -3
d'où f ( 4) = 4 * - 1 - 3 = - 4 - 3 = - 7
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f ( - 8) = 0 et f ( - 1 ) = 13
( 13 - 0 ) / ( - 1 + 8 ) = 13/7 donc ax = 13 x / 7
f ( - 1 ) = 13
- 1 * 13/7 + b = 13
- 13/7 + b = 13
b = 13 + 13/7 = 91/7 + 13/7 = 104/7
f (x) = 13 x / 7 + 104/ 7
d'où f ( - 8) = - 8 * 13/7 + 104/7 = - 104/7 + 104/7 = 0
allez fais le dernier