3(x+4)^2+15(x+4)-18=0

解

3 (x + 4)^{2} + 15 (x + 4) - 18 = 0

x = - 3, x = - 10

解答ステップ

3 (x + 4)^{2} + 15 (x + 4) - 18 = 0

拡張

3 (x + 4)^{2} + 15 (x + 4) - 18 : 3 x^{2} + 39 x + 90

3 x^{2} + 39 x + 90 = 0

解くとthe二次式

x_{1, 2} = \frac{- 39 \pm 3 9 ^{2} - 4 \cdot 3 \cdot 90}{2 \cdot 3}

3 9^{2} - 4 \cdot 3 \cdot 90 = 21

x_{1, 2} = \frac{- 39 \pm 21}{2 \cdot 3}

解を分離する

x_{1} = \frac{- 39 + 21}{2 \cdot 3}, x_{2} = \frac{- 39 - 21}{2 \cdot 3}

x = \frac{- 39 + 21}{2 \cdot 3} : - 3

x = \frac{- 39 - 21}{2 \cdot 3} : - 10

二次equationの解:

x = - 3, x = - 10