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受欢迎的代数 >

x^2=0.2x+3

解答

x^{2} = 0.2 x + 3

解答

x = \frac{1 + 301}{10}, x = \frac{1 - 301}{10}

+1

十进制

x = 1.83493 \dots, x = - 1.63493 \dots

求解步骤

x^{2} = 0.2 x + 3

在两边乘以

10

x^{2} \cdot 10 = 2 x + 30

将

30

para o lado esquerdo

x^{2} \cdot 10 - 30 = 2 x

将

2 x

para o lado esquerdo

x^{2} \cdot 10 - 30 - 2 x = 0

改写成标准形式

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

10 x^{2} - 2 x - 30 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 2 ) \pm ( - 2 ) ^{2} - 4 \cdot 10 ( - 30 )}{2 \cdot 10}

(- 2)^{2} - 4 \cdot 10 (- 30) = 2301

x_{1, 2} = \frac{- ( - 2 ) \pm 2 301}{2 \cdot 10}

将解分隔开

x_{1} = \frac{- ( - 2 ) + 2 301}{2 \cdot 10}, x_{2} = \frac{- ( - 2 ) - 2 301}{2 \cdot 10}

x = \frac{- ( - 2 ) + 2 301}{2 \cdot 10} : \frac{1 + 301}{10}

x = \frac{- ( - 2 ) - 2 301}{2 \cdot 10} : \frac{1 - 301}{10}

二次方程组的解是:

x = \frac{1 + 301}{10}, x = \frac{1 - 301}{10}

作图

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