Odpowiedź:
f(x) = - 1/2x² + 6x - 2
- 1/2x² + 6x - 2 = 8
- 1/2x² + 6x - 2 - 8 = 0
- 1/2x² + 6x - 10 = 0
a = - 1/2 , b = 6 , c = - 10
Δ = b² - 4ac = 6² - 4 * (- 1/2) * (- 10) = 36 - 2 * 10 = 36 - 20 = 16
√Δ = √16 = 4
x₁ = ( - b - √Δ)/2a = ( - 6 - 4)/(- 1/2 * 2) = - 10/(- 1) = 10/1 = 10
x₂ = ( - b + √Δ)/2a = (-6 + 4)/(- 1/2 * 2) = - 2/(- 1) = 2/1 = 2
