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受欢迎的代数 >

r^2+12r+4=7

解答

r^{2} + 12 r + 4 = 7

解答

r = - 6 + 39, r = - 6 - 39

+1

十进制

r = 0.24499 \dots, r = - 12.24499 \dots

求解步骤

r^{2} + 12 r + 4 = 7

将

7

para o lado esquerdo

r^{2} + 12 r - 3 = 0

使用求根公式求解

r_{1, 2} = \frac{- 12 \pm 1 2 ^{2} - 4 \cdot 1 \cdot ( - 3 )}{2 \cdot 1}

1 2^{2} - 4 \cdot 1 \cdot (- 3) = 239

r_{1, 2} = \frac{- 12 \pm 2 39}{2 \cdot 1}

将解分隔开

r_{1} = \frac{- 12 + 2 39}{2 \cdot 1}, r_{2} = \frac{- 12 - 2 39}{2 \cdot 1}

r = \frac{- 12 + 2 39}{2 \cdot 1} : - 6 + 39

r = \frac{- 12 - 2 39}{2 \cdot 1} : - 6 - 39

二次方程组的解是:

r = - 6 + 39, r = - 6 - 39

作图

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