solvefor x,81x^2+72x+28=0

解

x, 81 x^{2} + 72 x + 28 = 0

x = - \frac{4}{9} + i \frac{2 3}{9}, x = - \frac{4}{9} - i \frac{2 3}{9}

解答ステップ

81 x^{2} + 72 x + 28 = 0

解くとthe二次式

x_{1, 2} = \frac{- 72 \pm 7 2 ^{2} - 4 \cdot 81 \cdot 28}{2 \cdot 81}

簡素化

7 2^{2} - 4 \cdot 81 \cdot 28 : 363 i

x_{1, 2} = \frac{- 72 \pm 36 3 i}{2 \cdot 81}

解を分離する

x_{1} = \frac{- 72 + 36 3 i}{2 \cdot 81}, x_{2} = \frac{- 72 - 36 3 i}{2 \cdot 81}

x = \frac{- 72 + 36 3 i}{2 \cdot 81} : - \frac{4}{9} + i \frac{2 3}{9}

x = \frac{- 72 - 36 3 i}{2 \cdot 81} : - \frac{4}{9} - i \frac{2 3}{9}

二次equationの解:

x = - \frac{4}{9} + i \frac{2 3}{9}, x = - \frac{4}{9} - i \frac{2 3}{9}