-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 = -36.0 -18 = 2.0
x" = -7 + √841 2*-9 = -7 + 29.0 -18 = 22.0 -18 = -1.22222222222
x' = 162.0
x" = -99.0
S = {x ∈ R / x' = 162.0, x" = -99.0 }