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受欢迎的代数 >

-0.2x^2+8x+20=-2.4x+97.4

解答

- 0.2 x^{2} + 8 x + 20 = - 2.4 x + 97.4

解答

x = 9, x = 43

求解步骤

- 0.2 x^{2} + 8 x + 20 = - 2.4 x + 97.4

在两边乘以

10

- 2 x^{2} + 80 x + 200 = - 24 x + 974

将

974

para o lado esquerdo

- 2 x^{2} + 80 x - 774 = - 24 x

将

24 x

para o lado esquerdo

- 2 x^{2} + 104 x - 774 = 0

使用求根公式求解

x_{1, 2} = \frac{- 104 \pm 10 4 ^{2} - 4 ( - 2 ) ( - 774 )}{2 ( - 2 )}

10 4^{2} - 4 (- 2) (- 774) = 68

x_{1, 2} = \frac{- 104 \pm 68}{2 ( - 2 )}

将解分隔开

x_{1} = \frac{- 104 + 68}{2 ( - 2 )}, x_{2} = \frac{- 104 - 68}{2 ( - 2 )}

x = \frac{- 104 + 68}{2 ( - 2 )} : 9

x = \frac{- 104 - 68}{2 ( - 2 )} : 43

二次方程组的解是:

x = 9, x = 43

作图

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