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受欢迎的代数 >

z^2=8z+20

解答

z^{2} = 8 z + 20

解答

z = 10, z = - 2

求解步骤

z^{2} = 8 z + 20

将

20

para o lado esquerdo

z^{2} - 20 = 8 z

将

8 z

para o lado esquerdo

z^{2} - 20 - 8 z = 0

改写成标准形式

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

z^{2} - 8 z - 20 = 0

使用求根公式求解

z_{1, 2} = \frac{- ( - 8 ) \pm ( - 8 ) ^{2} - 4 \cdot 1 \cdot ( - 20 )}{2 \cdot 1}

(- 8)^{2} - 4 \cdot 1 \cdot (- 20) = 12

z_{1, 2} = \frac{- ( - 8 ) \pm 12}{2 \cdot 1}

将解分隔开

z_{1} = \frac{- ( - 8 ) + 12}{2 \cdot 1}, z_{2} = \frac{- ( - 8 ) - 12}{2 \cdot 1}

z = \frac{- ( - 8 ) + 12}{2 \cdot 1} : 10

z = \frac{- ( - 8 ) - 12}{2 \cdot 1} : - 2

二次方程组的解是:

z = 10, z = - 2

作图

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