-4x2 -18x +22 = 0
ax2 bx c = 0
a = -4
b = -18
c = 22
Δ = b2-4ac
Δ = -18² - (4 * -4 * 22)
Δ = 324 - (4*-88)
Δ = 324 - (-352)
Δ = 676 Δ > 0
-4x2-18x+22=0
x = -b ∓ √Δ 2a
x' = 18 - √676 2*-4 = 18 - 26.0 -8 = -8.0 -8 = 1.0
x" = 18 + √676 2*-4 = 18 + 26.0 -8 = 44.0 -8 = -5.5
x' = 16.0
x" = -88.0
S = {x ∈ R / x' = 16.0, x" = -88.0 }