5x^2-20x-60=0

解

5 x^{2} - 20 x - 60 = 0

x = 6, x = - 2

解答ステップ

5 x^{2} - 20 x - 60 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 20 ) \pm ( - 20 ) ^{2} - 4 \cdot 5 ( - 60 )}{2 \cdot 5}

(- 20)^{2} - 4 \cdot 5 (- 60) = 40

x_{1, 2} = \frac{- ( - 20 ) \pm 40}{2 \cdot 5}

解を分離する

x_{1} = \frac{- ( - 20 ) + 40}{2 \cdot 5}, x_{2} = \frac{- ( - 20 ) - 40}{2 \cdot 5}

x = \frac{- ( - 20 ) + 40}{2 \cdot 5} : 6

x = \frac{- ( - 20 ) - 40}{2 \cdot 5} : - 2

二次equationの解:

x = 6, x = - 2