-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 }