-12x2 +14x +20 = 0
ax2 bx c = 0
a = -12
b = 14
c = 20
Δ = b2-4ac
Δ = 14² - (4 * -12 * 20)
Δ = 196 - (4*-240)
Δ = 196 - (-960)
Δ = 1156 Δ > 0
-12x2+14x+20=0
x = -b ∓ √Δ 2a
x' = -14 - √1156 2*-12 = -14 - 34.0 -24 = -48.0 -24 = 2.0
x" = -14 + √1156 2*-12 = -14 + 34.0 -24 = 20.0 -24 = -0.833333333333
x' = 288.0
x" = -120.0
S = {x ∈ R / x' = 288.0, x" = -120.0 }