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 = -10.0 10 = -1.0
x" = 7 + √289 2*5 = 7 + 17.0 10 = 24.0 10 = 2.4
x' = -25.0
x" = 60.0
S = {x ∈ R / x' = -25.0, x" = 60.0 }