|x^2-4x-5|=5

解

x^{2} - 4 x - 5 = 5

x = 2 - 14 or x = 0 or x = 4 or x = 2 + 14

十進法表記

x = - 1.74165 \dots, x = 0, x = 4, x = 5.74165 \dots

解答ステップ

x^{2} - 4 x - 5 = 5

絶対規則を適用する:

∣ u ∣ = a, a > 0

の場合は

u = a

u = - a

x^{2} - 4 x - 5 = - 5 or x^{2} - 4 x - 5 = 5

x^{2} - 4 x - 5 = - 5 or x^{2} - 4 x - 5 = 5

(x = 0 or x = 4) or (x = 2 - 14 or x = 2 + 14)

x = 2 - 14 or x = 0 or x = 4 or x = 2 + 14