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受欢迎的代数 >

(x-3)(x+3)=4,x^2-9=4x^2-36

解答

(x - 3) (x + 3) = 4, x^{2} - 9 = 4 x^{2} - 36

解答

x = 13, x = - 13

+1

十进制

x = 3.60555 \dots, x = - 3.60555 \dots

求解步骤

(x - 3) (x + 3) = 4

展开

(x - 3) (x + 3) : x^{2} - 9

x^{2} - 9 = 4

将

4

para o lado esquerdo

x^{2} - 13 = 0

使用求根公式求解

x_{1, 2} = \frac{- 0 \pm 0 ^{2} - 4 \cdot 1 \cdot ( - 13 )}{2 \cdot 1}

0^{2} - 4 \cdot 1 \cdot (- 13) = 213

x_{1, 2} = \frac{- 0 \pm 2 13}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- 0 + 2 13}{2 \cdot 1}, x_{2} = \frac{- 0 - 2 13}{2 \cdot 1}

x = \frac{- 0 + 2 13}{2 \cdot 1} : 13

x = \frac{- 0 - 2 13}{2 \cdot 1} : - 13

二次方程组的解是:

x = 13, x = - 13

作图

流行的例子

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