3x^2-2x-18=0

解

3 x^{2} - 2 x - 18 = 0

x = \frac{1 + 55}{3}, x = \frac{1 - 55}{3}

十進法表記

x = 2.80539 \dots, x = - 2.13873 \dots

解答ステップ

3 x^{2} - 2 x - 18 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 2 ) \pm ( - 2 ) ^{2} - 4 \cdot 3 ( - 18 )}{2 \cdot 3}

(- 2)^{2} - 4 \cdot 3 (- 18) = 255

x_{1, 2} = \frac{- ( - 2 ) \pm 2 55}{2 \cdot 3}

解を分離する

x_{1} = \frac{- ( - 2 ) + 2 55}{2 \cdot 3}, x_{2} = \frac{- ( - 2 ) - 2 55}{2 \cdot 3}

x = \frac{- ( - 2 ) + 2 55}{2 \cdot 3} : \frac{1 + 55}{3}

x = \frac{- ( - 2 ) - 2 55}{2 \cdot 3} : \frac{1 - 55}{3}

二次equationの解:

x = \frac{1 + 55}{3}, x = \frac{1 - 55}{3}