15x2 +14x -16 = 0
ax2 bx c = 0
a = 15
b = 14
c = -16
Δ = b2-4ac
Δ = 14² - (4 * 15 * -16)
Δ = 196 - (4*-240)
Δ = 196 - (-960)
Δ = 1156 Δ > 0
15x2+14x-16=0
x = -b ∓ √Δ 2a
x' = -14 - √1156 2*15 = -14 - 34.0 30 = -48.0 30 = -1.6
x" = -14 + √1156 2*15 = -14 + 34.0 30 = 20.0 30 = 0.666666666667
x' = -360.0
x" = 150.0
S = {x ∈ R / x' = -360.0, x" = 150.0 }