5x2 +7x -12 = 0
ax2 bx c = 0
a = 5
b = 7
c = -12
Δ = b2-4ac
Δ = 7² - (4 * 5 * -12)
Δ = 49 - (4*-60)
Δ = 49 - (-240)
Δ = 289 Δ > 0
5x2+7x-12=0
x = -b ∓ √Δ 2a
x' = -7 - √289 2*5 = -7 - 17.0 10 = -24.0 10 = -2.4
x" = -7 + √289 2*5 = -7 + 17.0 10 = 10.0 10 = 1.0
x' = -60.0
x" = 25.0
S = {x ∈ R / x' = -60.0, x" = 25.0 }