bonjour
12x² = 5x + 2
12x² - 5x - 2 = 0
équation du second degré
on la résout en calculant le discriminant : (a = 12 ; b = -5 ; c = -2)
Δ = b² − 4ac = (-5)² -4*12*(-2) = 25 + 96 = 121 = 11²
Δ > 0 il y a deux solutions
x1 = (5 - 11)/24 = -6/24 = -1/4
x2 = (5 + 11)/24 = 16/24 = 2/3
S = {-1/4 ; 2/3}