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受欢迎的代数 >

x^2-20x=5

解答

x^{2} - 20 x = 5

解答

x = 10 + 105, x = 10 - 105

+1

十进制

x = 20.24695 \dots, x = - 0.24695 \dots

求解步骤

x^{2} - 20 x = 5

将

5

para o lado esquerdo

x^{2} - 20 x - 5 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 20 ) \pm ( - 20 ) ^{2} - 4 \cdot 1 \cdot ( - 5 )}{2 \cdot 1}

(- 20)^{2} - 4 \cdot 1 \cdot (- 5) = 2105

x_{1, 2} = \frac{- ( - 20 ) \pm 2 105}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- ( - 20 ) + 2 105}{2 \cdot 1}, x_{2} = \frac{- ( - 20 ) - 2 105}{2 \cdot 1}

x = \frac{- ( - 20 ) + 2 105}{2 \cdot 1} : 10 + 105

x = \frac{- ( - 20 ) - 2 105}{2 \cdot 1} : 10 - 105

二次方程组的解是:

x = 10 + 105, x = 10 - 105

作图

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