-1x2 +16x -15 = 0
ax2 bx c = 0
a = -1
b = 16
c = -15
Δ = b2-4ac
Δ = 16² - (4 * -1 * -15)
Δ = 256 - (4*15)
Δ = 256 - (60)
Δ = 196 Δ > 0
-x2+16x-15=0
x = -b ∓ √Δ 2a
x' = -16 - √196 2*-1 = -16 - 14.0 -2 = -30.0 -2 = 15.0
x" = -16 + √196 2*-1 = -16 + 14.0 -2 = -2.0 -2 = 1.0
x' = 15.0
x" = 1.0
S = {x ∈ R / x' = 15.0, x" = 1.0 }