sqrt(5)x^2-3x-2sqrt(5)=0

解

5 x^{2} - 3 x - 25 = 0

x = 5, x = - \frac{2}{5}

十進法表記

x = 2.23606 \dots, x = - 0.89442 \dots

解答ステップ

5 x^{2} - 3 x - 25 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 3 ) \pm ( - 3 ) ^{2} - 4 5 ( - 2 5 )}{2 5}

(- 3)^{2} - 45 (- 25) = 7

x_{1, 2} = \frac{- ( - 3 ) \pm 7}{2 5}

解を分離する

x_{1} = \frac{- ( - 3 ) + 7}{2 5}, x_{2} = \frac{- ( - 3 ) - 7}{2 5}

x = \frac{- ( - 3 ) + 7}{2 5} : 5

x = \frac{- ( - 3 ) - 7}{2 5} : - \frac{2}{5}

二次equationの解:

x = 5, x = - \frac{2}{5}