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受欢迎的代数 >

x^2-18x-2=0

解答

x^{2} - 18 x - 2 = 0

解答

x = 9 + 83, x = 9 - 83

+1

十进制

x = 18.11043 \dots, x = - 0.11043 \dots

求解步骤

x^{2} - 18 x - 2 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 18 ) \pm ( - 18 ) ^{2} - 4 \cdot 1 \cdot ( - 2 )}{2 \cdot 1}

(- 18)^{2} - 4 \cdot 1 \cdot (- 2) = 283

x_{1, 2} = \frac{- ( - 18 ) \pm 2 83}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- ( - 18 ) + 2 83}{2 \cdot 1}, x_{2} = \frac{- ( - 18 ) - 2 83}{2 \cdot 1}

x = \frac{- ( - 18 ) + 2 83}{2 \cdot 1} : 9 + 83

x = \frac{- ( - 18 ) - 2 83}{2 \cdot 1} : 9 - 83

二次方程组的解是:

x = 9 + 83, x = 9 - 83

作图

流行的例子

completesquare 2x^2-12x+23

co m pl e t es q u a re 2 x^{2} - 12 x + 23

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9 x - 2 = - 5 x^{2}

- 2 x^{2} - x + 28 = 0

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