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受欢迎的代数 >

-1x^2+7x+5=0

解答

- 1 x^{2} + 7 x + 5 = 0

解答

x = - \frac{- 7 + 69}{2}, x = \frac{7 + 69}{2}

+1

十进制

x = - 0.65331 \dots, x = 7.65331 \dots

求解步骤

- 1 \cdot x^{2} + 7 x + 5 = 0

整理后得

- x^{2} + 7 x + 5 = 0

使用求根公式求解

x_{1, 2} = \frac{- 7 \pm 7 ^{2} - 4 ( - 1 ) \cdot 5}{2 ( - 1 )}

7^{2} - 4 (- 1) \cdot 5 = 69

x_{1, 2} = \frac{- 7 \pm 69}{2 ( - 1 )}

将解分隔开

x_{1} = \frac{- 7 + 69}{2 ( - 1 )}, x_{2} = \frac{- 7 - 69}{2 ( - 1 )}

x = \frac{- 7 + 69}{2 ( - 1 )} : - \frac{- 7 + 69}{2}

x = \frac{- 7 - 69}{2 ( - 1 )} : \frac{7 + 69}{2}

二次方程组的解是:

x = - \frac{- 7 + 69}{2}, x = \frac{7 + 69}{2}

作图

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