-1x2 -x +12 = 0
ax2 bx c = 0
a = -1
b = -1
c = 12
Δ = b2-4ac
Δ = -² - (4 * -1 * 12)
Δ = 1 - (4*-12)
Δ = 1 - (-48)
Δ = 49 Δ > 0
-x2-x+12=0
x = -b ∓ √Δ 2a
x' = 1 - √49 2*-1 = 1 - 7.0 -2 = -6.0 -2 = 3.0
x" = 1 + √49 2*-1 = 1 + 7.0 -2 = 8.0 -2 = -4.0
x' = 3.0
x" = -4.0
S = {x ∈ R / x' = 3.0, x" = -4.0 }