solvefor x,x^2+3x+1=0

解

x, x^{2} + 3 x + 1 = 0

x = \frac{- 3 + 5}{2}, x = \frac{- 3 - 5}{2}

十進法表記

x = - 0.38196 \dots, x = - 2.61803 \dots

解答ステップ

x^{2} + 3 x + 1 = 0

解くとthe二次式

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

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

x_{1, 2} = \frac{- 3 \pm 5}{2 \cdot 1}

解を分離する

x_{1} = \frac{- 3 + 5}{2 \cdot 1}, x_{2} = \frac{- 3 - 5}{2 \cdot 1}

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

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

二次equationの解:

x = \frac{- 3 + 5}{2}, x = \frac{- 3 - 5}{2}