Bonjour,
(x+1)² = 9
Tu dois simplifier :
x²+ 2*x*1 + 1² = 9
x² + 2x+1=9
x² + 2x - 8 = 0
Δ = b²-4ac
Δ = 2²-4*1*(-8)
Δ = 36
x1 = [tex]\frac{-b-\sqrt{delta} }{2a} = \frac{-2-6}{2} = -4[/tex]
x2 = [tex]\frac{-b+\sqrt{delta} }{2a} = \frac{-2+6}{2} = 2[/tex]
S = {-4; 2}
Bonne journée
