5x2 -7x -6 = 0
ax2 bx c = 0
a = 5
b = -7
c = -6
Δ = b2-4ac
Δ = -7² - (4 * 5 * -6)
Δ = 49 - (4*-30)
Δ = 49 - (-120)
Δ = 169 Δ > 0
5x2-7x-6=0
x = -b ∓ √Δ 2a
x' = 7 - √169 2*5 = 7 - 13.0 10 = -6.0 10 = -0.6
x" = 7 + √169 2*5 = 7 + 13.0 10 = 20.0 10 = 2.0
x' = -15.0
x" = 50.0
S = {x ∈ R / x' = -15.0, x" = 50.0 }