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受欢迎的代数 >

2x^2=13x+45

解答

2 x^{2} = 13 x + 45

解答

x = 9, x = - \frac{5}{2}

+1

十进制

x = 9, x = - 2.5

求解步骤

2 x^{2} = 13 x + 45

将

45

para o lado esquerdo

2 x^{2} - 45 = 13 x

将

13 x

para o lado esquerdo

2 x^{2} - 45 - 13 x = 0

改写成标准形式

a x^{2} + b x + c = 0

2 x^{2} - 13 x - 45 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 13 ) \pm ( - 13 ) ^{2} - 4 \cdot 2 ( - 45 )}{2 \cdot 2}

(- 13)^{2} - 4 \cdot 2 (- 45) = 23

x_{1, 2} = \frac{- ( - 13 ) \pm 23}{2 \cdot 2}

将解分隔开

x_{1} = \frac{- ( - 13 ) + 23}{2 \cdot 2}, x_{2} = \frac{- ( - 13 ) - 23}{2 \cdot 2}

x = \frac{- ( - 13 ) + 23}{2 \cdot 2} : 9

x = \frac{- ( - 13 ) - 23}{2 \cdot 2} : - \frac{5}{2}

二次方程组的解是:

x = 9, x = - \frac{5}{2}

作图

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