5x2 +21x +22 = 0
ax2 bx c = 0
a = 5
b = 21
c = 22
Δ = b2-4ac
Δ = 21² - (4 * 5 * 22)
Δ = 441 - (4*110)
Δ = 441 - (440)
Δ = 1 Δ > 0
5x2+21x+22=0
x = -b ∓ √Δ 2a
x' = -21 - √1 2*5 = -21 - 1.0 10 = -22.0 10 = -2.2
x" = -21 + √1 2*5 = -21 + 1.0 10 = -20.0 10 = -2.0
x' = -55.0
x" = -50.0
S = {x ∈ R / x' = -55.0, x" = -50.0 }