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受欢迎的代数 >

20x^2+3x-9=0

解答

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

解答

x = \frac{3}{5}, x = - \frac{3}{4}

+1

十进制

x = 0.6, x = - 0.75

求解步骤

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

使用求根公式求解

x_{1, 2} = \frac{- 3 \pm 3 ^{2} - 4 \cdot 20 ( - 9 )}{2 \cdot 20}

3^{2} - 4 \cdot 20 (- 9) = 27

x_{1, 2} = \frac{- 3 \pm 27}{2 \cdot 20}

将解分隔开

x_{1} = \frac{- 3 + 27}{2 \cdot 20}, x_{2} = \frac{- 3 - 27}{2 \cdot 20}

x = \frac{- 3 + 27}{2 \cdot 20} : \frac{3}{5}

x = \frac{- 3 - 27}{2 \cdot 20} : - \frac{3}{4}

二次方程组的解是:

x = \frac{3}{5}, x = - \frac{3}{4}

作图

流行的例子

99 = x^{2} - 1

(x - 4)^{2} - 81 = 0

4 y - y^{2} = 0

81 x^{2} - 100 = 0

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