bonjour
f (x) = x² - 14 x +13
α = 14/2 = 7
β = 7² - 14*7 + 13 = 49 - 98 + 13 = - 36
f (x) = ( x - 7)² - 36
f (x) = ( x - 7 - 6 ) ( x - 7 + 6 )
f (x) = ( x - 13 ) ( x - 1 )
f (x) = 0 pour x = 13 ou 1
x - ∞ 1 13 + ∞
x - 13 - - 0 +
x - 1 - 0 + +
produit + 0 - 0 +
| x - 3 | = 1
| x - 3 | = x - 3 si x - 3 ≥ 0 ⇔ x ≥ 3
x - ∞ 3 +∞
| x - 3 | - ( x - 3 ) 0 x - 3
- ( x - 3 ) = 1
- x + 3 = 1
- x = - 2
x = 2
x - 3 = 1
x = 4
S ( 2 ; 4 )
