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受欢迎的代数 >

(x+5)(x+4)=156

解答

(x + 5) (x + 4) = 156

解答

x = 8, x = - 17

求解步骤

(x + 5) (x + 4) = 156

展开

(x + 5) (x + 4) : x^{2} + 9 x + 20

x^{2} + 9 x + 20 = 156

将

156

para o lado esquerdo

x^{2} + 9 x - 136 = 0

使用求根公式求解

x_{1, 2} = \frac{- 9 \pm 9 ^{2} - 4 \cdot 1 \cdot ( - 136 )}{2 \cdot 1}

9^{2} - 4 \cdot 1 \cdot (- 136) = 25

x_{1, 2} = \frac{- 9 \pm 25}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- 9 + 25}{2 \cdot 1}, x_{2} = \frac{- 9 - 25}{2 \cdot 1}

x = \frac{- 9 + 25}{2 \cdot 1} : 8

x = \frac{- 9 - 25}{2 \cdot 1} : - 17

二次方程组的解是:

x = 8, x = - 17

作图

流行的例子

9x^2-63=8x^2+2x

9 x^{2} - 63 = 8 x^{2} + 2 x

2 x^{2} = x - 7

x^{2} + 6 x + 5 = 8

6 x^{2} = 47 x + 8

49-121x^2-170x=0

49 - 121 x^{2} - 170 x = 0