15x2 -19x -10 = 0
ax2 bx c = 0
a = 15
b = -19
c = -10
Δ = b2-4ac
Δ = -19² - (4 * 15 * -10)
Δ = 361 - (4*-150)
Δ = 361 - (-600)
Δ = 961 Δ > 0
15x2-19x-10=0
x = -b ∓ √Δ 2a
x' = 19 - √961 2*15 = 19 - 31.0 30 = -12.0 30 = -0.4
x" = 19 + √961 2*15 = 19 + 31.0 30 = 50.0 30 = 1.66666666667
x' = -90.0
x" = 375.0
S = {x ∈ R / x' = -90.0, x" = 375.0 }