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受欢迎的代数 >

25=15x-1.86x^2

解答

25 = 15 x - 1.86 x^{2}

解答

x = \frac{25 ( 15 - 39 )}{93}, x = \frac{25 ( 15 + 39 )}{93}

+1

十进制

x = 2.35349 \dots, x = 5.71102 \dots

求解步骤

25 = 15 x - 1.86 x^{2}

在两边乘以

100

2500 = 1500 x - 186 x^{2}

交换两边

1500 x - 186 x^{2} = 2500

将

2500

para o lado esquerdo

1500 x - 186 x^{2} - 2500 = 0

改写成标准形式

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

- 186 x^{2} + 1500 x - 2500 = 0

使用求根公式求解

x_{1, 2} = \frac{- 1500 \pm 150 0 ^{2} - 4 ( - 186 ) ( - 2500 )}{2 ( - 186 )}

150 0^{2} - 4 (- 186) (- 2500) = 10039

x_{1, 2} = \frac{- 1500 \pm 100 39}{2 ( - 186 )}

将解分隔开

x_{1} = \frac{- 1500 + 100 39}{2 ( - 186 )}, x_{2} = \frac{- 1500 - 100 39}{2 ( - 186 )}

x = \frac{- 1500 + 100 39}{2 ( - 186 )} : \frac{25 ( 15 - 39 )}{93}

x = \frac{- 1500 - 100 39}{2 ( - 186 )} : \frac{25 ( 15 + 39 )}{93}

二次方程组的解是:

x = \frac{25 ( 15 - 39 )}{93}, x = \frac{25 ( 15 + 39 )}{93}

作图

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