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受欢迎的代数 >

solvefor x,2x^2+5x=8

解答

x, 2 x^{2} + 5 x = 8

解答

x = \frac{- 5 + 89}{4}, x = \frac{- 5 - 89}{4}

+1

十进制

x = 1.10849 \dots, x = - 3.60849 \dots

求解步骤

2 x^{2} + 5 x = 8

将

8

para o lado esquerdo

2 x^{2} + 5 x - 8 = 0

使用求根公式求解

x_{1, 2} = \frac{- 5 \pm 5 ^{2} - 4 \cdot 2 ( - 8 )}{2 \cdot 2}

5^{2} - 4 \cdot 2 (- 8) = 89

x_{1, 2} = \frac{- 5 \pm 89}{2 \cdot 2}

将解分隔开

x_{1} = \frac{- 5 + 89}{2 \cdot 2}, x_{2} = \frac{- 5 - 89}{2 \cdot 2}

x = \frac{- 5 + 89}{2 \cdot 2} : \frac{- 5 + 89}{4}

x = \frac{- 5 - 89}{2 \cdot 2} : \frac{- 5 - 89}{4}

二次方程组的解是:

x = \frac{- 5 + 89}{4}, x = \frac{- 5 - 89}{4}

作图

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