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受欢迎的代数 >

2d^2-4d-5=0

解答

2 d^{2} - 4 d - 5 = 0

解答

d = \frac{2 + 14}{2}, d = \frac{2 - 14}{2}

+1

十进制

d = 2.87082 \dots, d = - 0.87082 \dots

求解步骤

2 d^{2} - 4 d - 5 = 0

使用求根公式求解

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

(- 4)^{2} - 4 \cdot 2 (- 5) = 214

d_{1, 2} = \frac{- ( - 4 ) \pm 2 14}{2 \cdot 2}

将解分隔开

d_{1} = \frac{- ( - 4 ) + 2 14}{2 \cdot 2}, d_{2} = \frac{- ( - 4 ) - 2 14}{2 \cdot 2}

d = \frac{- ( - 4 ) + 2 14}{2 \cdot 2} : \frac{2 + 14}{2}

d = \frac{- ( - 4 ) - 2 14}{2 \cdot 2} : \frac{2 - 14}{2}

二次方程组的解是:

d = \frac{2 + 14}{2}, d = \frac{2 - 14}{2}

作图

流行的例子

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