-15x2 -18x -3 = 0
ax2 bx c = 0
a = -15
b = -18
c = -3
Δ = b2-4ac
Δ = -18² - (4 * -15 * -3)
Δ = 324 - (4*45)
Δ = 324 - (180)
Δ = 144 Δ > 0
-15x2-18x-3=0
x = -b ∓ √Δ 2a
x' = 18 - √144 2*-15 = 18 - 12.0 -30 = 6.0 -30 = -0.2
x" = 18 + √144 2*-15 = 18 + 12.0 -30 = 30.0 -30 = -1.0
x' = -45.0
x" = -225.0
S = {x ∈ R / x' = -45.0, x" = -225.0 }