-12x2 +3x +15 = 0
ax2 bx c = 0
a = -12
b = 3
c = 15
Δ = b2-4ac
Δ = 3² - (4 * -12 * 15)
Δ = 9 - (4*-180)
Δ = 9 - (-720)
Δ = 729 Δ > 0
-12x2+3x+15=0
x = -b ∓ √Δ 2a
x' = -3 - √729 2*-12 = -3 - 27.0 -24 = -30.0 -24 = 1.25
x" = -3 + √729 2*-12 = -3 + 27.0 -24 = 24.0 -24 = -1.0
x' = 180.0
x" = -144.0
S = {x ∈ R / x' = 180.0, x" = -144.0 }