-4x2 +13x +17 = 0
ax2 bx c = 0
a = -4
b = 13
c = 17
Δ = b2-4ac
Δ = 13² - (4 * -4 * 17)
Δ = 169 - (4*-68)
Δ = 169 - (-272)
Δ = 441 Δ > 0
-4x2+13x+17=0
x = -b ∓ √Δ 2a
x' = -13 - √441 2*-4 = -13 - 21.0 -8 = -34.0 -8 = 4.25
x" = -13 + √441 2*-4 = -13 + 21.0 -8 = 8.0 -8 = -1.0
x' = 68.0
x" = -16.0
S = {x ∈ R / x' = 68.0, x" = -16.0 }