(2x + 3)² - (x - 2)² = 0
2x + 3 = x - 2
2x - x = - 2 - 3
x = - 5
2x + 3 = - (x - 2)
2x + 3 + x - 2 = 0
3x = - 3 + 2
3x = - 1
x = - 1/3
S= {- 5 ; - 1/3}
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3(x - 1)² + 4x - 4 = 0
3(x² - 2x + 1) + 4x - 4 = 0
3x² - 6x + 3 + 4x - 4 = 0
3x² - 2x - 1 = 0
Δ = b² - 4ac
Δ = (- 2)² - 4 x 3 x (- 1)
Δ = 4 - (- 12)
Δ = 16
Comme Δ > 0, l'équation a deux racines réelles distinctes.
[tex]x_1_,_2= \frac{-b\pm \sqrt{\Delta} }{2a} \\ \\ x_1= \frac{2-4}{2\times3} =- \frac{1}{3} \\ \\ x_2= \frac{2+4}{2\times3} =1[/tex]
S= {- 1/3 ; 1}
