-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 }