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受欢迎的代数 >

x^2+7x=68.75

解答

x^{2} + 7 x = 68.75

解答

x = \frac{11}{2}, x = - \frac{25}{2}

+1

十进制

x = 5.5, x = - 12.5

求解步骤

x^{2} + 7 x = 68.75

在两边乘以

100

100 x^{2} + 700 x = 6875

将

6875

para o lado esquerdo

100 x^{2} + 700 x - 6875 = 0

使用求根公式求解

x_{1, 2} = \frac{- 700 \pm 70 0 ^{2} - 4 \cdot 100 ( - 6875 )}{2 \cdot 100}

70 0^{2} - 4 \cdot 100 (- 6875) = 1800

x_{1, 2} = \frac{- 700 \pm 1800}{2 \cdot 100}

将解分隔开

x_{1} = \frac{- 700 + 1800}{2 \cdot 100}, x_{2} = \frac{- 700 - 1800}{2 \cdot 100}

x = \frac{- 700 + 1800}{2 \cdot 100} : \frac{11}{2}

x = \frac{- 700 - 1800}{2 \cdot 100} : - \frac{25}{2}

二次方程组的解是:

x = \frac{11}{2}, x = - \frac{25}{2}

作图

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