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 }