-5x^2+30x+80=0

解

- 5 x^{2} + 30 x + 80 = 0

x = - 2, x = 8

解答ステップ

- 5 x^{2} + 30 x + 80 = 0

解くとthe二次式

x_{1, 2} = \frac{- 30 \pm 3 0 ^{2} - 4 ( - 5 ) \cdot 80}{2 ( - 5 )}

3 0^{2} - 4 (- 5) \cdot 80 = 50

x_{1, 2} = \frac{- 30 \pm 50}{2 ( - 5 )}

解を分離する

x_{1} = \frac{- 30 + 50}{2 ( - 5 )}, x_{2} = \frac{- 30 - 50}{2 ( - 5 )}

x = \frac{- 30 + 50}{2 ( - 5 )} : - 2

x = \frac{- 30 - 50}{2 ( - 5 )} : 8

二次equationの解:

x = - 2, x = 8