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受欢迎的代数 >

2x^2+2x-15=0

解答

2 x^{2} + 2 x - 15 = 0

解答

x = \frac{- 1 + 31}{2}, x = - \frac{1 + 31}{2}

+1

十进制

x = 2.28388 \dots, x = - 3.28388 \dots

求解步骤

2 x^{2} + 2 x - 15 = 0

使用求根公式求解

x_{1, 2} = \frac{- 2 \pm 2 ^{2} - 4 \cdot 2 ( - 15 )}{2 \cdot 2}

2^{2} - 4 \cdot 2 (- 15) = 231

x_{1, 2} = \frac{- 2 \pm 2 31}{2 \cdot 2}

将解分隔开

x_{1} = \frac{- 2 + 2 31}{2 \cdot 2}, x_{2} = \frac{- 2 - 2 31}{2 \cdot 2}

x = \frac{- 2 + 2 31}{2 \cdot 2} : \frac{- 1 + 31}{2}

x = \frac{- 2 - 2 31}{2 \cdot 2} : - \frac{1 + 31}{2}

二次方程组的解是:

x = \frac{- 1 + 31}{2}, x = - \frac{1 + 31}{2}

作图

流行的例子

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x^{2} - 27 x + 65 = - 13 x

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