-4x2 +19x -12 = 0
ax2 bx c = 0
a = -4
b = 19
c = -12
Δ = b2-4ac
Δ = 19² - (4 * -4 * -12)
Δ = 361 - (4*48)
Δ = 361 - (192)
Δ = 169 Δ > 0
-4x2+19x-12=0
x = -b ∓ √Δ 2a
x' = -19 - √169 2*-4 = -19 - 13.0 -8 = -32.0 -8 = 4.0
x" = -19 + √169 2*-4 = -19 + 13.0 -8 = -6.0 -8 = 0.75
x' = 64.0
x" = 12.0
S = {x ∈ R / x' = 64.0, x" = 12.0 }