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受欢迎的代数 >

3x^2-3x-9=0

解答

3 x^{2} - 3 x - 9 = 0

解答

x = \frac{1 + 13}{2}, x = \frac{1 - 13}{2}

+1

十进制

x = 2.30277 \dots, x = - 1.30277 \dots

求解步骤

3 x^{2} - 3 x - 9 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 3 ) \pm ( - 3 ) ^{2} - 4 \cdot 3 ( - 9 )}{2 \cdot 3}

(- 3)^{2} - 4 \cdot 3 (- 9) = 313

x_{1, 2} = \frac{- ( - 3 ) \pm 3 13}{2 \cdot 3}

将解分隔开

x_{1} = \frac{- ( - 3 ) + 3 13}{2 \cdot 3}, x_{2} = \frac{- ( - 3 ) - 3 13}{2 \cdot 3}

x = \frac{- ( - 3 ) + 3 13}{2 \cdot 3} : \frac{1 + 13}{2}

x = \frac{- ( - 3 ) - 3 13}{2 \cdot 3} : \frac{1 - 13}{2}

二次方程组的解是:

x = \frac{1 + 13}{2}, x = \frac{1 - 13}{2}

作图

流行的例子

- x^{2} + 5 x - 1 = 0

2 w^{2} - 11 w = - 12

x^{2} = 2 x - x^{2}

(r + 1)^{2} = 0

x + 1 < 34