|x^2-2x-5|=2

解

x^{2} - 2 x - 5 = 2

x = 1 - 22 or x = - 1 or x = 3 or x = 1 + 22

十進法表記

x = - 1.82842 \dots, x = - 1, x = 3, x = 3.82842 \dots

解答ステップ

x^{2} - 2 x - 5 = 2

絶対規則を適用する:

∣ u ∣ = a, a > 0

の場合は

u = a

u = - a

x^{2} - 2 x - 5 = - 2 or x^{2} - 2 x - 5 = 2

x^{2} - 2 x - 5 = - 2 or x^{2} - 2 x - 5 = 2

(x = - 1 or x = 3) or (x = 1 - 22 or x = 1 + 22)

x = 1 - 22 or x = - 1 or x = 3 or x = 1 + 22