-1x2 +22x +23 = 0
ax2 bx c = 0
a = -1
b = 22
c = 23
Δ = b2-4ac
Δ = 22² - (4 * -1 * 23)
Δ = 484 - (4*-23)
Δ = 484 - (-92)
Δ = 576 Δ > 0
-x2+22x+23=0
x = -b ∓ √Δ 2a
x' = -22 - √576 2*-1 = -22 - 24.0 -2 = -46.0 -2 = 23.0
x" = -22 + √576 2*-1 = -22 + 24.0 -2 = 2.0 -2 = -1.0
x' = 23.0
x" = -1.0
S = {x ∈ R / x' = 23.0, x" = -1.0 }