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受欢迎的代数 >

x^2-6x-20=7

解答

x^{2} - 6 x - 20 = 7

解答

x = 9, x = - 3

求解步骤

x^{2} - 6 x - 20 = 7

将

7

para o lado esquerdo

x^{2} - 6 x - 27 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 6 ) \pm ( - 6 ) ^{2} - 4 \cdot 1 \cdot ( - 27 )}{2 \cdot 1}

(- 6)^{2} - 4 \cdot 1 \cdot (- 27) = 12

x_{1, 2} = \frac{- ( - 6 ) \pm 12}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- ( - 6 ) + 12}{2 \cdot 1}, x_{2} = \frac{- ( - 6 ) - 12}{2 \cdot 1}

x = \frac{- ( - 6 ) + 12}{2 \cdot 1} : 9

x = \frac{- ( - 6 ) - 12}{2 \cdot 1} : - 3

二次方程组的解是:

x = 9, x = - 3

作图

流行的例子

- 11 x - 1 = - 3 x^{2} + 3

5 x^{2} - 11 x + 6 = 0

2 x^{2} - 242 = 0

- 12 x^{2} + 120 x = 0

3 x^{2} + 30 x - 27 = 6