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 = -8.0 2 = -4.0
x" = -1 + √49 2*1 = -1 + 7.0 2 = 6.0 2 = 3.0
x' = -4.0
x" = 3.0
S = {x ∈ R / x' = -4.0, x" = 3.0 }