-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 = -8.0 -8 = 1.0
x" = 13 + √441 2*-4 = 13 + 21.0 -8 = 34.0 -8 = -4.25
x' = 16.0
x" = -68.0
S = {x ∈ R / x' = 16.0, x" = -68.0 }