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受欢迎的代数 >

x^2-20=-8x

解答

x^{2} - 20 = - 8 x

解答

x = 2, x = - 10

求解步骤

x^{2} - 20 = - 8 x

将

8 x

para o lado esquerdo

x^{2} - 20 + 8 x = 0

改写成标准形式

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

x^{2} + 8 x - 20 = 0

使用求根公式求解

x_{1, 2} = \frac{- 8 \pm 8 ^{2} - 4 \cdot 1 \cdot ( - 20 )}{2 \cdot 1}

8^{2} - 4 \cdot 1 \cdot (- 20) = 12

x_{1, 2} = \frac{- 8 \pm 12}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- 8 + 12}{2 \cdot 1}, x_{2} = \frac{- 8 - 12}{2 \cdot 1}

x = \frac{- 8 + 12}{2 \cdot 1} : 2

x = \frac{- 8 - 12}{2 \cdot 1} : - 10

二次方程组的解是:

x = 2, x = - 10

作图

流行的例子

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

(x+1)^2-(x+1)/2 =18

(x + 1)^{2} - \frac{x + 1}{2} = 18

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16 x^{2} - 40 = 0

4x(8x)+8-12=15x^2-12(25+16)

4 x (8 x) + 8 - 12 = 15 x^{2} - 12 (25 + 16)