bonjour
f ( 0) = 1 et f ( - 1 ) = 3
( 3 - 1 ) : ( - 1 - 0 ) = - 2 donc ax = - 2 x
(f - 1 ) = 3
- 1 * - 2 + b = 3
⇔ 2 + b = 3
⇔ b = 3 - 2 = 1
donc f (x) = - 2 x + 1
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g ( 0 ) = 0 et g ( 4 ) = 2
( 2 - 0 ) : ( 4 - 0 ) = 2 /4 = 1 /2 donc g (x) = x /2 = fonction linéaire
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h ( 0 ) = 3 et h ( 1) = 4
( 4 - 3 ) : ( 1 - 0 ) = 1 /1 = 1 donc ax = x
h ( 1) = 4
1 * 1 + b = 4
⇔ b = 4 - 1 = 3
donc h (x) = x + 3
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k ( 0 ) = 5 et k ( 2) = 0
( 0 - 5 ) : ( 2 - 0 ) = - 5 /2 donc ax = 5 x /2 = 2.5 x
k ( 2) = 0
2 * 2.5 + b = 0
⇔ b = - 5
donc k (x) = 2.5 x - 5
