x^2+3x-40=0

解

x^{2} + 3 x - 40 = 0

x = 5, x = - 8

解答ステップ

x^{2} + 3 x - 40 = 0

解くとthe二次式

x_{1, 2} = \frac{- 3 \pm 3 ^{2} - 4 \cdot 1 \cdot ( - 40 )}{2 \cdot 1}

3^{2} - 4 \cdot 1 \cdot (- 40) = 13

x_{1, 2} = \frac{- 3 \pm 13}{2 \cdot 1}

解を分離する

x_{1} = \frac{- 3 + 13}{2 \cdot 1}, x_{2} = \frac{- 3 - 13}{2 \cdot 1}

x = \frac{- 3 + 13}{2 \cdot 1} : 5

x = \frac{- 3 - 13}{2 \cdot 1} : - 8

二次equationの解:

x = 5, x = - 8