-1x2 +15x +16 = 0
ax2 bx c = 0
a = -1
b = 15
c = 16
Δ = b2-4ac
Δ = 15² - (4 * -1 * 16)
Δ = 225 - (4*-16)
Δ = 225 - (-64)
Δ = 289 Δ > 0
-x2+15x+16=0
x = -b ∓ √Δ 2a
x' = -15 - √289 2*-1 = -15 - 17.0 -2 = -32.0 -2 = 16.0
x" = -15 + √289 2*-1 = -15 + 17.0 -2 = 2.0 -2 = -1.0
x' = 16.0
x" = -1.0
S = {x ∈ R / x' = 16.0, x" = -1.0 }