bonjour
x² + 1.5 x = 1
x² + 1.5 x - 1 =0
Δ = ( 1.5)² - 4 ( 1 * - 1 ) = 2.25 + 4 = 6.25 = 2.5 ²
x ₁ = ( - 1.5 - 2.5 ) / 2 = - 4/2 = - 2
x ₂ = ( - 1.5 + 2.5 ) / 2 = 1/2
S ( - 2 ; 1/2 )
4 x² + 4 x = - 1
4 x² + 4 x + 1 = 0
ici pas besoin de discriminant
( 2 x + 1 )² = 0 donc x = - 1/2
x² = - 3 x - 2
x² + 3 x + 2 = 0
Δ = 9 - 4 ( 1 *2) = 9 - 8 = 1
x 1 = ( - 3 - 1 ) / 2 = - 4 /2 = - 2
x 2 = ( - 3 + 1 ) / 2 = - 2 /2 = - 1
S ( - 2 ; - 1 )
- x² = - 12 + 4 x
- x² - 4 x + 12 = 0
Δ = 16 - 4 ( - 1 *12) = 16 + 48 = 64
x 1 = ( 4 - 8 ) / - 2 = - 4 /- 2 = 2
x 2 = ( 4 + 8 ) / - 2 = - 12/2 = - 6
S ( - 6 ; 2 )
3 x² - 12 x + 10 = - 2
3 x² - 12 x + 10 + 2 = 0
3 x² - 2 x + 2 = 0
Δ = 4 - 4 ( 3 * 2 ) = 4 - 24 = - 20
Δ < 0 donc pas de solution , la courbe ne coupe pas l'axe des abscisses
2 x² + x - 1 = - 2
2 x² + x - 1 + 2 = 0
2 x² + x + 1 = 0
Δ = 1 - 4 ( 2 * 1 ) = 1 - 8 = - 7
Δ < 0 donc pas de solution
