bonjour
f (x) = - x² + 2 x + 3
f ( - 2 ) = - ( - 2 )² + 2 ( - 2 ) + 3 = - 4 - 4 + 3 = - 5
f ( - 1 ) = - ( - 1 )² + 2 ( - 1 ) + 3 = - 1 - 2 + 3 = 0
f ( 0) = 3
f ( 0.5 ) = - ( 0.5 )² + 2 * 0.5 + 3 = - 0.25 + 1 + 3 = 3.75
tu fais pareil pour la suite, tu remplaces x par sa valeur
2 ) f (x) = 3
- x² + 2 x + 3 = 3
- x² + 2 x = 0
- x ( x - 2 ) = 0
x = 0 ou 2
f (x) = 4 - ( x - 1 )²
f (x) = 4 - ( x² - 2 x + 1 ) = 4 - x² + 2 x - 1 = - x² + 2 x + 3
f (x) = 0
( 2 + x - 1 ) ( 2 - x + 1 ) = 0
( x + 1 ) ( - x + 3 ) = 0
x = - 1 ou 3
g (x) = 2 x - 3
fonction affine de la forme ax + b
f (x) = g (x)
- x² + 2 x + 3 = 2 x - 3
- x² + 2 x - 2 x = - 3 - 3
- x² = - 6
x² = 6
x = √ 6 ou - √ 6
