-5x^2-40x+45=0

解

- 5 x^{2} - 40 x + 45 = 0

x = - 9, x = 1

解答ステップ

- 5 x^{2} - 40 x + 45 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 40 ) \pm ( - 40 ) ^{2} - 4 ( - 5 ) \cdot 45}{2 ( - 5 )}

(- 40)^{2} - 4 (- 5) \cdot 45 = 50

x_{1, 2} = \frac{- ( - 40 ) \pm 50}{2 ( - 5 )}

解を分離する

x_{1} = \frac{- ( - 40 ) + 50}{2 ( - 5 )}, x_{2} = \frac{- ( - 40 ) - 50}{2 ( - 5 )}

x = \frac{- ( - 40 ) + 50}{2 ( - 5 )} : - 9

x = \frac{- ( - 40 ) - 50}{2 ( - 5 )} : 1

二次equationの解:

x = - 9, x = 1