-18x2 +23x +16 = 0
ax2 bx c = 0
a = -18
b = 23
c = 16
Δ = b2-4ac
Δ = 23² - (4 * -18 * 16)
Δ = 529 - (4*-288)
Δ = 529 - (-1152)
Δ = 1681 Δ > 0
-18x2+23x+16=0
x = -b ∓ √Δ 2a
x' = -23 - √1681 2*-18 = -23 - 41.0 -36 = -64.0 -36 = 1.77777777778
x" = -23 + √1681 2*-18 = -23 + 41.0 -36 = 18.0 -36 = -0.5
x' = 576.0
x" = -162.0
S = {x ∈ R / x' = 576.0, x" = -162.0 }