bonjour
f (x) = 4 - ( x + 1 )²
f (x ) = 4 - ( x² + 2 x + 1 )
f (x) = 4 - x² - 2 x - 1
f (x) = - x² - 2 x + 3
f (0) = 3
f ( 3) = - ( 3 )² - 2 *3 + 3 = - 9 - 6 + 3 = - 12
f ( - 1 ) = - ( - 1 )² - 2 * - 1 + 3 = - 1 + 2 + 3 = 4
f (x) = 0
mieux vaut la forme factorisée
( 1 - x ) ( x - 3 ) = 0
x = 1 ou 3
- x² - 2 x + 3 = 3
- x² - 2 x + 3 - 3 = 0
- x ( x + 2 ) = 0
x = 0 ou - 2
- x² - 2 x + 3 = 2
- x² - 2 x + 3 - 2 = 0
- x² - 2 x + 1 = 0
- ( x - 1 )² = 0
x = 1