д) x² - 20x - 20x - 100 = 0;
x² - 40x - 100 = 0;
D = (-40)² - 4 * 1 * (-100) = 1600 + 400 = 2000;
x₁ = (40 + √2000) / (2 * 1) = (40 + 20√5) / 2 = 20 + 10√5;
x₂ = (40 - √2000) / (2 * 1) = (40 - 20√5) / 2 = 20 - 10√5
Ответ: x₁ = 20 + 10√5, x₂ = 20 - 10√5