2x^2+8x-90=0

解

2 x^{2} + 8 x - 90 = 0

x = 5, x = - 9

解答ステップ

2 x^{2} + 8 x - 90 = 0

解くとthe二次式

x_{1, 2} = \frac{- 8 \pm 8 ^{2} - 4 \cdot 2 ( - 90 )}{2 \cdot 2}

8^{2} - 4 \cdot 2 (- 90) = 28

x_{1, 2} = \frac{- 8 \pm 28}{2 \cdot 2}

解を分離する

x_{1} = \frac{- 8 + 28}{2 \cdot 2}, x_{2} = \frac{- 8 - 28}{2 \cdot 2}

x = \frac{- 8 + 28}{2 \cdot 2} : 5

x = \frac{- 8 - 28}{2 \cdot 2} : - 9

二次equationの解:

x = 5, x = - 9