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受欢迎的代数 >

x(x-3)=2x^2+4x

解答

x (x - 3) = 2 x^{2} + 4 x

解答

x = - 7, x = 0

求解步骤

x (x - 3) = 2 x^{2} + 4 x

展开

x (x - 3) : x^{2} - 3 x

x^{2} - 3 x = 2 x^{2} + 4 x

将

4 x

para o lado esquerdo

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

将

2 x^{2}

para o lado esquerdo

- x^{2} - 7 x = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 7 ) \pm ( - 7 ) ^{2} - 4 ( - 1 ) \cdot 0}{2 ( - 1 )}

(- 7)^{2} - 4 (- 1) \cdot 0 = 7

x_{1, 2} = \frac{- ( - 7 ) \pm 7}{2 ( - 1 )}

将解分隔开

x_{1} = \frac{- ( - 7 ) + 7}{2 ( - 1 )}, x_{2} = \frac{- ( - 7 ) - 7}{2 ( - 1 )}

x = \frac{- ( - 7 ) + 7}{2 ( - 1 )} : - 7

x = \frac{- ( - 7 ) - 7}{2 ( - 1 )} : 0

二次方程组的解是:

x = - 7, x = 0

作图

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