-9x2 +19x -2 = 0
ax2 bx c = 0
a = -9
b = 19
c = -2
Δ = b2-4ac
Δ = 19² - (4 * -9 * -2)
Δ = 361 - (4*18)
Δ = 361 - (72)
Δ = 289 Δ > 0
-9x2+19x-2=0
x = -b ∓ √Δ 2a
x' = -19 - √289 2*-9 = -19 - 17.0 -18 = -36.0 -18 = 2.0
x" = -19 + √289 2*-9 = -19 + 17.0 -18 = -2.0 -18 = 0.111111111111
x' = 162.0
x" = 9.0
S = {x ∈ R / x' = 162.0, x" = 9.0 }