-15x2 -12x +3 = 0
ax2 bx c = 0
a = -15
b = -12
c = 3
Δ = b2-4ac
Δ = -12² - (4 * -15 * 3)
Δ = 144 - (4*-45)
Δ = 144 - (-180)
Δ = 324 Δ > 0
-15x2-12x+3=0
x = -b ∓ √Δ 2a
x' = 12 - √324 2*-15 = 12 - 18.0 -30 = -6.0 -30 = 0.2
x" = 12 + √324 2*-15 = 12 + 18.0 -30 = 30.0 -30 = -1.0
x' = 45.0
x" = -225.0
S = {x ∈ R / x' = 45.0, x" = -225.0 }