5x2 +11x -12 = 0
ax2 bx c = 0
a = 5
b = 11
c = -12
Δ = b2-4ac
Δ = 11² - (4 * 5 * -12)
Δ = 121 - (4*-60)
Δ = 121 - (-240)
Δ = 361 Δ > 0
5x2+11x-12=0
x = -b ∓ √Δ 2a
x' = -11 - √361 2*5 = -11 - 19.0 10 = -30.0 10 = -3.0
x" = -11 + √361 2*5 = -11 + 19.0 10 = 8.0 10 = 0.8
x' = -75.0
x" = 20.0
S = {x ∈ R / x' = -75.0, x" = 20.0 }