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受欢迎的代数 >

5x-17=(x+3)(x-3)

解答

5 x - 17 = (x + 3) (x - 3)

解答

x = \frac{5}{2} + i \frac{7}{2}, x = \frac{5}{2} - i \frac{7}{2}

求解步骤

5 x - 17 = (x + 3) (x - 3)

展开

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

5 x - 17 = x^{2} - 9

交换两边

x^{2} - 9 = 5 x - 17

将

17

para o lado esquerdo

x^{2} + 8 = 5 x

将

5 x

para o lado esquerdo

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

改写成标准形式

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

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

使用求根公式求解

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

化简

(- 5)^{2} - 4 \cdot 1 \cdot 8 : 7 i

x_{1, 2} = \frac{- ( - 5 ) \pm 7 i}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- ( - 5 ) + 7 i}{2 \cdot 1}, x_{2} = \frac{- ( - 5 ) - 7 i}{2 \cdot 1}

x = \frac{- ( - 5 ) + 7 i}{2 \cdot 1} : \frac{5}{2} + i \frac{7}{2}

x = \frac{- ( - 5 ) - 7 i}{2 \cdot 1} : \frac{5}{2} - i \frac{7}{2}

二次方程组的解是:

x = \frac{5}{2} + i \frac{7}{2}, x = \frac{5}{2} - i \frac{7}{2}

作图

流行的例子

9 x = 4 - 2 x^{2}

3 x^{2} - x^{2} = 1800

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

solvefor x,3x^2+mx+3=0

so l v e f or x, 3 x^{2} + m x + 3 = 0

x^{2} = 8 x - 12