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受欢迎的代数 >

(1-2x-x^2)=0

解答

(1 - 2 x - x^{2}) = 0

解答

x = - 1 - 2, x = 2 - 1

+1

十进制

x = - 2.41421 \dots, x = 0.41421 \dots

求解步骤

(1 - 2 x - x^{2}) = 0

整理后得

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

改写成标准形式

a x^{2} + b x + c = 0

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

使用求根公式求解

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

(- 2)^{2} - 4 (- 1) \cdot 1 = 22

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

将解分隔开

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

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

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

二次方程组的解是:

x = - 1 - 2, x = 2 - 1

作图

流行的例子

t^{2} = - 3 t - 4

8 y^{2} - y + 2 = 0

u^{2} - 4 u = 0

8 x^{2} + 3 = - 4 x

3 n^{2} + n - 310 = 0