-9x2 -7x +22 = 0
ax2 bx c = 0
a = -9
b = -7
c = 22
Δ = b2-4ac
Δ = -7² - (4 * -9 * 22)
Δ = 49 - (4*-198)
Δ = 49 - (-792)
Δ = 841 Δ > 0
-9x2-7x+22=0
x = -b ∓ √Δ 2a
x' = 7 - √841 2*-9 = 7 - 29.0 -18 = -22.0 -18 = 1.22222222222
x" = 7 + √841 2*-9 = 7 + 29.0 -18 = 36.0 -18 = -2.0
x' = 99.0
x" = -162.0
S = {x ∈ R / x' = 99.0, x" = -162.0 }