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受欢迎的代数 >

8x^2-22x=21

解答

8 x^{2} - 22 x = 21

解答

x = \frac{7}{2}, x = - \frac{3}{4}

+1

十进制

x = 3.5, x = - 0.75

求解步骤

8 x^{2} - 22 x = 21

将

21

para o lado esquerdo

8 x^{2} - 22 x - 21 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 22 ) \pm ( - 22 ) ^{2} - 4 \cdot 8 ( - 21 )}{2 \cdot 8}

(- 22)^{2} - 4 \cdot 8 (- 21) = 34

x_{1, 2} = \frac{- ( - 22 ) \pm 34}{2 \cdot 8}

将解分隔开

x_{1} = \frac{- ( - 22 ) + 34}{2 \cdot 8}, x_{2} = \frac{- ( - 22 ) - 34}{2 \cdot 8}

x = \frac{- ( - 22 ) + 34}{2 \cdot 8} : \frac{7}{2}

x = \frac{- ( - 22 ) - 34}{2 \cdot 8} : - \frac{3}{4}

二次方程组的解是:

x = \frac{7}{2}, x = - \frac{3}{4}

作图

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