x^2-2sqrt(5)x+4=0

解

x^{2} - 25 x + 4 = 0

x = 5 + 1, x = 5 - 1

十進法表記

x = 3.23606 \dots, x = 1.23606 \dots

解答ステップ

x^{2} - 25 x + 4 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 2 5 ) \pm ( - 2 5 ) ^{2} - 4 \cdot 1 \cdot 4}{2 \cdot 1}

(- 25)^{2} - 4 \cdot 1 \cdot 4 = 2

x_{1, 2} = \frac{- ( - 2 5 ) \pm 2}{2 \cdot 1}

解を分離する

x_{1} = \frac{- ( - 2 5 ) + 2}{2 \cdot 1}, x_{2} = \frac{- ( - 2 5 ) - 2}{2 \cdot 1}

x = \frac{- ( - 2 5 ) + 2}{2 \cdot 1} : 5 + 1

x = \frac{- ( - 2 5 ) - 2}{2 \cdot 1} : 5 - 1

二次equationの解:

x = 5 + 1, x = 5 - 1