3x^2+15x+12=0

解

3 x^{2} + 15 x + 12 = 0

x = - 1, x = - 4

解答ステップ

3 x^{2} + 15 x + 12 = 0

解くとthe二次式

x_{1, 2} = \frac{- 15 \pm 1 5 ^{2} - 4 \cdot 3 \cdot 12}{2 \cdot 3}

1 5^{2} - 4 \cdot 3 \cdot 12 = 9

x_{1, 2} = \frac{- 15 \pm 9}{2 \cdot 3}

解を分離する

x_{1} = \frac{- 15 + 9}{2 \cdot 3}, x_{2} = \frac{- 15 - 9}{2 \cdot 3}

x = \frac{- 15 + 9}{2 \cdot 3} : - 1

x = \frac{- 15 - 9}{2 \cdot 3} : - 4

二次equationの解:

x = - 1, x = - 4