x² -2x-24=0
on a alors :
a = 1, b=-2 , c=-24
∆ = b²-4ax
∆ = (-2)²-(4×1×-24)
∆ = 4+96 = 100
∆ > 0 donc 2 solutions
x1 = (-b-√∆)/2a
x2 = (-b+√∆)/2a
x1 = (2-√100)/2 = (2-10)/2 = -8/2 = -4
x2 = (2+√100)/2 = (2+10)/2 = 12/2 = 6
donc les solutions sont -4 et 6
