-12x2 -8x +7 = 0
ax2 bx c = 0
a = -12
b = -8
c = 7
Δ = b2-4ac
Δ = -8² - (4 * -12 * 7)
Δ = 64 - (4*-84)
Δ = 64 - (-336)
Δ = 400 Δ > 0
-12x2-8x+7=0
x = -b ∓ √Δ 2a
x' = 8 - √400 2*-12 = 8 - 20.0 -24 = -12.0 -24 = 0.5
x" = 8 + √400 2*-12 = 8 + 20.0 -24 = 28.0 -24 = -1.16666666667
x' = 72.0
x" = -168.0
S = {x ∈ R / x' = 72.0, x" = -168.0 }