5x2 -14x -19 = 0
ax2 bx c = 0
a = 5
b = -14
c = -19
Δ = b2-4ac
Δ = -14² - (4 * 5 * -19)
Δ = 196 - (4*-95)
Δ = 196 - (-380)
Δ = 576 Δ > 0
5x2-14x-19=0
x = -b ∓ √Δ 2a
x' = 14 - √576 2*5 = 14 - 24.0 10 = -10.0 10 = -1.0
x" = 14 + √576 2*5 = 14 + 24.0 10 = 38.0 10 = 3.8
x' = -25.0
x" = 95.0
S = {x ∈ R / x' = -25.0, x" = 95.0 }