-4x2 +22x -18 = 0
ax2 bx c = 0
a = -4
b = 22
c = -18
Δ = b2-4ac
Δ = 22² - (4 * -4 * -18)
Δ = 484 - (4*72)
Δ = 484 - (288)
Δ = 196 Δ > 0
-4x2+22x-18=0
x = -b ∓ √Δ 2a
x' = -22 - √196 2*-4 = -22 - 14.0 -8 = -36.0 -8 = 4.5
x" = -22 + √196 2*-4 = -22 + 14.0 -8 = -8.0 -8 = 1.0
x' = 72.0
x" = 16.0
S = {x ∈ R / x' = 72.0, x" = 16.0 }