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 = -50.0 30 = -1.66666666667
x" = -19 + √961 2*15 = -19 + 31.0 30 = 12.0 30 = 0.4
x' = -375.0
x" = 90.0
S = {x ∈ R / x' = -375.0, x" = 90.0 }