bonjour
5 x² - 3 x +2 = - 3 x + 7
5 x² - 3 x + 3 x = 7 - 2
5 x² = 5
x² = 1
x = √1 ou - √1
- x² + x + 1 = 3 x - 7
- x² + x - 3 x = - 7 - 1
- x² - 2 x = - 8
- x² - 2 x + 8 = 0
Δ < 0 pas de solution dans R
3 x² + x + 2 = 2
3 x² + x = 2 - 2
3 x² + x = 0
x = 0
x² - x - 9 = x +2
x² - x - x = 2 + 9
x² - 2 x = 11
x² - 2 x - 11 = 0
Δ = 4 - 4 ( 1 * - 11 ) = 4 + 44 = 49
x 1 = ( 2 - 7 ) / 2 = - 5 /2 = - 2.5
tu as les racines
x 2 = ( 2 + 7 ) / 2 = 9/2 = 4.5
