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受欢迎的代数 >

(x-3)(x+2)-(x-1)(x-2)=(x+4)*(x-7)

解答

(x - 3) \cdot (x + 2) - (x - 1) \cdot (x - 2) = (x + 4) \cdot (x - 7)

解答

x = \frac{5 + 105}{2}, x = \frac{5 - 105}{2}

+1

十进制

x = 7.62347 \dots, x = - 2.62347 \dots

求解步骤

(x - 3) (x + 2) - (x - 1) (x - 2) = (x + 4) (x - 7)

展开

(x - 3) (x + 2) - (x - 1) (x - 2) : 2 x - 8

展开

(x + 4) (x - 7) : x^{2} - 3 x - 28

2 x - 8 = x^{2} - 3 x - 28

交换两边

x^{2} - 3 x - 28 = 2 x - 8

将

8

para o lado esquerdo

x^{2} - 3 x - 20 = 2 x

将

2 x

para o lado esquerdo

x^{2} - 5 x - 20 = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - 5 ) \pm ( - 5 ) ^{2} - 4 \cdot 1 \cdot ( - 20 )}{2 \cdot 1}

(- 5)^{2} - 4 \cdot 1 \cdot (- 20) = 105

x_{1, 2} = \frac{- ( - 5 ) \pm 105}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- ( - 5 ) + 105}{2 \cdot 1}, x_{2} = \frac{- ( - 5 ) - 105}{2 \cdot 1}

x = \frac{- ( - 5 ) + 105}{2 \cdot 1} : \frac{5 + 105}{2}

x = \frac{- ( - 5 ) - 105}{2 \cdot 1} : \frac{5 - 105}{2}

二次方程组的解是:

x = \frac{5 + 105}{2}, x = \frac{5 - 105}{2}

作图

流行的例子

kx^2+(k-1)x-1=0

k x^{2} + (k - 1) x - 1 = 0

- 5 c^{2} + 4 = - 81

u(2u-1)a+(u-1)(2u-1)b+4u(1-u)c=0

u (2 u - 1) a + (u - 1) (2 u - 1) b + 4 u (1 - u) c = 0

0 = x^{2} - 10 x + 16

0 = x^{2} - 10 x + 18