22x2 -13x -9 = 0

ax2 bx c = 0

a = 22

b = -13

c = -9

Δ = b2-4ac

Δ = -13² - (4 * 22 * -9)

Δ = 169 - (4*-198)

Δ = 169 - (-792)

Δ = 961      Δ > 0

22x2-13x-9=0

x = -b ∓ √Δ 2a

x' = 13 - √961 2*22 = 13 - 31.0 44 = -18.0 44 = -0.409090909091

x" = 13 + √961 2*22 = 13 + 31.0 44 = 44.0 44 = 1.0

x' = -198.0

x" = 484.0

S = {x ∈ R / x' = -198.0, x" = 484.0 }