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受欢迎的代数 >

-x^2+5x-1=0

解答

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

解答

x = \frac{5 - 21}{2}, x = \frac{5 + 21}{2}

+1

十进制

x = 0.20871 \dots, x = 4.79128 \dots

求解步骤

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

使用求根公式求解

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

5^{2} - 4 (- 1) (- 1) = 21

x_{1, 2} = \frac{- 5 \pm 21}{2 ( - 1 )}

将解分隔开

x_{1} = \frac{- 5 + 21}{2 ( - 1 )}, x_{2} = \frac{- 5 - 21}{2 ( - 1 )}

x = \frac{- 5 + 21}{2 ( - 1 )} : \frac{5 - 21}{2}

x = \frac{- 5 - 21}{2 ( - 1 )} : \frac{5 + 21}{2}

二次方程组的解是:

x = \frac{5 - 21}{2}, x = \frac{5 + 21}{2}

作图

流行的例子

2 w^{2} - 11 w = - 12

x^{2} = 2 x - x^{2}

(r + 1)^{2} = 0

x + 1 < 34

\frac{5}{8} = \frac{x}{7}