5x^2-40x-100=0

解

5 x^{2} - 40 x - 100 = 0

x = 10, x = - 2

解答ステップ

5 x^{2} - 40 x - 100 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 40 ) \pm ( - 40 ) ^{2} - 4 \cdot 5 ( - 100 )}{2 \cdot 5}

(- 40)^{2} - 4 \cdot 5 (- 100) = 60

x_{1, 2} = \frac{- ( - 40 ) \pm 60}{2 \cdot 5}

解を分離する

x_{1} = \frac{- ( - 40 ) + 60}{2 \cdot 5}, x_{2} = \frac{- ( - 40 ) - 60}{2 \cdot 5}

x = \frac{- ( - 40 ) + 60}{2 \cdot 5} : 10

x = \frac{- ( - 40 ) - 60}{2 \cdot 5} : - 2

二次equationの解:

x = 10, x = - 2