-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 = -2.0 -8 = 0.25
x" = 7 + √81 2*-4 = 7 + 9.0 -8 = 16.0 -8 = -2.0
x' = 4.0
x" = -32.0
S = {x ∈ R / x' = 4.0, x" = -32.0 }