-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 = -30.0 -30 = 1.0
x" = -18 + √144 2*-15 = -18 + 12.0 -30 = -6.0 -30 = 0.2
x' = 225.0
x" = 45.0
S = {x ∈ R / x' = 225.0, x" = 45.0 }