-4x2 +13x +12 = 0
ax2 bx c = 0
a = -4
b = 13
c = 12
Δ = b2-4ac
Δ = 13² - (4 * -4 * 12)
Δ = 169 - (4*-48)
Δ = 169 - (-192)
Δ = 361 Δ > 0
-4x2+13x+12=0
x = -b ∓ √Δ 2a
x' = -13 - √361 2*-4 = -13 - 19.0 -8 = -32.0 -8 = 4.0
x" = -13 + √361 2*-4 = -13 + 19.0 -8 = 6.0 -8 = -0.75
x' = 64.0
x" = -12.0
S = {x ∈ R / x' = 64.0, x" = -12.0 }