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受欢迎的代数 >

x(2x-4)=(x+1)(5-x)

解答

x (2 x - 4) = (x + 1) (5 - x)

解答

x = - \frac{- 4 + 31}{3}, x = \frac{4 + 31}{3}

+1

十进制

x = - 0.52258 \dots, x = 3.18925 \dots

求解步骤

x (2 x - 4) = (x + 1) (5 - x)

展开

x (2 x - 4) : 2 x^{2} - 4 x

展开

(x + 1) (5 - x) : 4 x - x^{2} + 5

2 x^{2} - 4 x = 4 x - x^{2} + 5

交换两边

4 x - x^{2} + 5 = 2 x^{2} - 4 x

将

4 x

para o lado esquerdo

- x^{2} + 8 x + 5 = 2 x^{2}

将

2 x^{2}

para o lado esquerdo

- 3 x^{2} + 8 x + 5 = 0

使用求根公式求解

x_{1, 2} = \frac{- 8 \pm 8 ^{2} - 4 ( - 3 ) \cdot 5}{2 ( - 3 )}

8^{2} - 4 (- 3) \cdot 5 = 231

x_{1, 2} = \frac{- 8 \pm 2 31}{2 ( - 3 )}

将解分隔开

x_{1} = \frac{- 8 + 2 31}{2 ( - 3 )}, x_{2} = \frac{- 8 - 2 31}{2 ( - 3 )}

x = \frac{- 8 + 2 31}{2 ( - 3 )} : - \frac{- 4 + 31}{3}

x = \frac{- 8 - 2 31}{2 ( - 3 )} : \frac{4 + 31}{3}

二次方程组的解是:

x = - \frac{- 4 + 31}{3}, x = \frac{4 + 31}{3}

作图

流行的例子

化简 (sqrt(6))/(sqrt(10))

s im pl i f y \frac{6}{10}

因式分解 125xy^3+20x^3y+100x^2y^2

f a c t or 125 x y^{3} + 20 x^{3} y + 100 x^{2} y^{2}

8 u - 21 = 2 u - 9

2 y - 5 = 4 y

x^{2} + 4 x + 4 = 18