-4x2 +7x +2 = 0
ax2 bx c = 0
a = -4
b = 7
c = 2
Δ = b2-4ac
Δ = 7² - (4 * -4 * 2)
Δ = 49 - (4*-8)
Δ = 49 - (-32)
Δ = 81 Δ > 0
-4x2+7x+2=0
x = -b ∓ √Δ 2a
x' = -7 - √81 2*-4 = -7 - 9.0 -8 = -16.0 -8 = 2.0
x" = -7 + √81 2*-4 = -7 + 9.0 -8 = 2.0 -8 = -0.25
x' = 32.0
x" = -4.0
S = {x ∈ R / x' = 32.0, x" = -4.0 }